While I get your general sentiment, I still think there's an overall greater benefit to proximity chat. Is it going to be bad sometimes? Absolutely. When aren't some anonymous interactions bad?
You're also losing moments where you're running around in the world and you overhear a group whom you've never seen before saying something like, "we really need a titan to get past this boss, why's it so hard to find someone who can tank?" You're playing your titan specifically made for tanking, you offer to join, you go raid. You might like the people you might not, the fact of the matter is it was a impromptu social experience that you can have. and choose to engage in fluidly.
Hell, even though Halo 2 was riddled with shit-talking. Some of the best social interactions I've ever experienced in a game came from there. I loved talking with people. I made good friends in social matchmaking. Something that's all but lost with the rise of party chat. The truly shitty thing is that, while I have a set group of friends that I play with? There are many that don't. And it's difficult to find people you like on the internet nowadays.
I'm pro opt-out. If you don't want to hear people, that's completely fine. Turn them off. I'd even agree with you that on your first play through you should have everyone muted. But when you're no longer on your first run through? When you've seen and experienced the content? That's when social legs need to carry this game. Having no proximity chat is, by and large, a deep blow to the game's community.