Who exactly was this game aimed at?

I wouldn't go that far. But I think they saw how much of a success the Citadel DLC was, and decided that laid back attitude could be used over the course of an entire game. I didn't like it, but others did.

I tend to think the same. Not bearing in mind that Citadel was a well done DLC, which had it's time and it's place, but not a full game.

I came to make my peace with the dialogue. Grudgingly, since I still don't like parts of it. But you can evade the most cringeworthy lines once you know what's lurking behind innocent looking dialogue options. Which on the other hand means, you can only use one or two reply options, which reduces diversity even further.

Once you realize that casual is not casual, but joke/sarcasm/goofy it helps.  They should have just had a dedicated option like sarcastic Hawke.

I'm guessing millennials? Early to mid 20s. So mature enough for the language and sex, but still young enough to relate to the characters and coming of age story. The protagonists are supposed to be around 22, so about that age group I imagine.

I disagree, the characters aren't meant to appeal to young teenagers, but they are still supposed to be quite young and inexperienced. And yeah, the tone is meant to be more light hearted and fun (compared to the trilogy), with joking banter. Like a Marvel movie? Or the rebooted Star Trek. 

The sex scenes themselves don't appear to be anything that would be considered that overly racy to most older teens/young adults today anyway, unless maybe, they are very conservative and don't watch much media or pop culture?

They are definitely aiming at younger audiences, probably around the same age as the Ryder twins. So early twenties.
I stopped trying to relate to the characters and their coming of age stories, so I'm just along for the ride. My poor husband keeps trying and restarting, each time trying to make his Sara look older, giving her grayer hair, but it's not working for him. He says he can't take Ryder seriously, and he can't expect anyone on her crew to take her seriously because she's just this kid who got her job handed to her by her dad.

Today's kids have mouths fouler than what I've heard in this game. In all seriousness though, this game is 18+ so no one under that should be playing it and complaining about it offending them.

As for the tone of the game, it's meant to be happier, lighter and hopeful.

As for the writing and characters? That's your opinion, but to me nothing about them are infantile. I'm 33 and can easily relate to Sara, who is 22.

There were only a handful of options for Ryder that made me actively cringe at how corny they were. The dialogue was no more infantile that other major science fiction franchises like Star Wars (original trilogy). The humor wasn't for everyone, but frankly it's a very small segment of the overall game. Honestly besides a few bits of banter between the crew members, who are intended to be close friends, the only mission that goes out of it's way to have humor is Liam's loyalty mission and if you enjoy sci-fi homages, you probably thought they were amusing.

I think we can all safely assume, by this point, that the answer is "Not you" apparently.

Oh yes! The days of no internet... how did we get by? We had to get creative!

Haha the Ryder twins are honestly more together than most people at that age, and the options we are given are far more tame than how vulgar we could get if someone annoyed us!

We had to go outside and put aside those mysteries of life, and I presume die in ignorance. Ghastly, no?

I spent most of my time exploring Roman ruins, which my childhood environment is ripe with. I still have some of the items I dug up back then. The head of a  flask, some nails. Oh, and we're also on the shores of a primeval ocean, so digging up fossilized shells was high on the agenda also.