The Catalyst is in the Citadel it is not THE Cidtadel

I agree with you that there is some inconsistencies there and that itis obvious that the Catalyst was a concept added into Bioware's thinking sometime after ME1.  It may have not even been thought of early in the development of ME3, since it would be a relatively simply matter to add in the scenes with the child to the beginning late in the development cycle of ME3.  Still, I don't view it as the "tragedy" other people do and I've found that the OP's ideas on this have always had some merit.

I now tend to think of the Catalyst as a computer virus inadvertently built into the programming of the Citadel systems.  It lies latent in the systems for thousands of years until a Reaper invasion brings it to life.  What does a virus think of itself once it's been resurrected and "assumes control" of a system?  Does it think of itself as being in control of that system and, by extension, anything connected to that system and, by further extension, anyone using that system?

I'm saying the language we speak can have multiple interpretation of what words mean.  I am part of a family doesn't literally mean we are a singular entity called family and I am just an aspect of this singular entity like a glorified spleen.  Equally a transmission is a part of a car but it does not control every aspect of the car.

I'm not arguing head cannon I'm arguing the language we speak and the flexibility in it to mean several things at once depending on the context applied to it. Sarcasm is entirely based on that. 

The Catalyst fits perfectly find with previous lore because the game never explicitly tells you how much of the Citadel the Catalyst actually has control of or access to.  Players make the choice to fill in the blanks. And as stated in OP it is done taking the most literal possible interpenetration of the Catalyst's words and filling in the blanks themselves.

Catalyst launched a surprise attack against Leviathan who thought they were untouchable gods of the galaxy. Some how I doubt the Catalyst was on the front line shooting at Leviathan and it's thralls.  That being said life living on the Citadel for literally thousands of years and not realizing it is a massive dormant mass relay is even less likely then the Catalyst needing some place safe to sit around while it's solution is put into practice.

Your skipping what you can't build a point against.  This has nothing to do the the Catalyst playing with language. This has everything to do with the player misunderstanding what was said, either unintentionally because it didn't make the point clear enough in game or intentionally because they don't care as long as it validates their opinion that (insert aspect of ME3) is bad.

Of course the Catalyst wasn't thought of for ME 1. How ever it's inclusion doesn't make it inconsistent with anything that came before unless you want it to. In fact the addition of the Catalyst possibly salvages the cluster fuck that is ME 1's ending and the entire plot of ME 2. There is absolutely no reason why Sovereign who was connected to the Citadel for a good 10-15 minutes minimum shouldn't have been able to activate the Mass Relay.  How ever it does make sense if Sovereign was attempting to run a full scan of the Citadel and all systems to make sure the Catalyst wasn't effected by the Prothean Scientists.  That delay would make it more realistic for Shepard to get there before the Relay is activated and we just hand wave the computer program that some how disables Sovereign's control of the Citadel Arms.

It also saves the hell out of ME2. Because lets be brutally honest here the over all story line of ME 2 is utter utter trash. From a narrative stance all it did was let us know the Reapers would be appearing in ME 3 and that Cerberus is basically magical.  Harbinger's obsession with humanity and Shepard makes no sense given their entire plan seems to be build a new Reaper and repeat what Sovereign tried.  And only after that failed do they head into the galaxy to start the harvest. Or they were already on their way and this was a pointless action on Harbinger's part. The two different times you can do the Arrival DLC makes the time line a bit murky.  How ever addition of the Catalyst suddenly makes Harbinger's side mission actually have some value to it.  Is humanity something different from the countless races that came before it? Is Shepard something special or is it just pure random luck?  Catalyst having the troops hold back while it finds out this information and how it could effect it's solution is a hell of a lot better then the original story line without the Catalyst.

It actually saves the narrative aspect of ME2 because in it's original form it is a game that would be fine if anyone but Shepard was the main character and it was treated as a side game to fill in the game's universe. Much in the same way Kingdom Hearts 358/2 Days is a side game that fills out the KH story a bit more but is doesn't add anything seriously new to the main story line.

No it isn't but the person sitting on the chair with the controller/mouse and keyboard combination is human. They are the ones that read the words on the screen. They are the ones that interpret it into what they want the words to mean. In this case the Catalyst saying it is part of the Citadel taking the meaning that it controls all of the citadel much like our own brains control our entire body. Thus creating the inconsistencies with the first game.  What you are doing is trying to shift the goal post here by trying to make it about the Catalyst and thus allowing you to claim it is an invalid argument. Then you switch to an insignificant line in relative terms of over all topic to focus all your effort on because that is easier ground to defend then actually addressing what has be said.

BTW I'm not reading your mind I'm reading your actions. There is a difference.

I pointed out all of this.  The Intelligence (Catalyst) took out the Leviathan before creating the first Reaper.  Whatever it was at the time, it was more powerful than the race that dominated the galaxy.  Sure, they were taken by surprise, but it's a damn big galaxy.

Then, in the Leviathan DLC, we learn that the Leviathan are still waiting for the Catalyst to find a workable solution.  It means they hadn't given up on it, thinking a billion years of experimentation was worth it.  They controlled the galaxy.  I'm sure plenty died for that to happen.  However, the Leviathan remained in hiding that whole time, observing.  The only reason they even entered the war was because Shepard forced their hand by letting the Reapers know they existed and where to find them.  With relatively low numbers, they couldn't survive a Reaper onslaught. 

I'm not sure where people came up with the Leviathan saying the Intelligence was a mistake.