I think I stopped looking to "fit in" when I realized my actual desire was to be genuinely loved by others, and to viscerally feel that was true. Being "in the group" was a poor substitute for this feeling. Many groups of people do not love each other very well, and these tend to be the groups that take a lot of energy to conform to.
If you're not marxist/anarchist, activist, vegan, and/or mask wearing, I can't honestly force myself to talk to you.
I feel pretty close to this but I'm still negotiating it for myself. I agree with what you said about "It's shorthand for giving a fuck," because that's how I see it as well. You have to give a fuck in order to love a person, and the dominant culture generates apathy towards others.
When I focus my efforts on covid-conscious people, I know at least that they believe in caring for themselves/others so strongly that they are willing to not only reject the dominant culture, but be materially harmed (harassed or assaulted in public, fired or not hired, verbally abused, shunned, denied services) because of it. This is a good start for being able to love in a friendship, even though it's not everything.