You can tell the author doesn't actually care about being a good person, what they care about is being seen by others as a good person.

They're not upset because they want to be good but they aren't as good as they previously thought, they're upset about the social consequences of continuing to do bad things. They want to continue to get away with it.

When they are presented with new understanding about a way in which people are bad and can do better, they see it like "ugh the liberals came up with more crap, guess we have to go along with it now". They'll do it but they're not happy about it. That's not "good person" vibes if you ask me.

Take for example the part about them laughing at the "Trump has small hands" joke. They claim the reason it's a bad joke is because it "apparently offends women who identify as men who have small hands and no penises". Sure, maybe that's a small part of it, but the main reason is that it belittles people with small hands. People in general. It belittles. Belittling people is what bad people do. But the author don't care about that, because they're not actually trying to be a good person. They sidestep any thoughts of improving themselves, any thoughts of "oh yeah I actually was wrong", and go straight for the scapegoat (i.e. "the joke would be funny if those meddling trans people weren't so demanding").

What very-likely happened is the author was presented with a big giant pile of reasons it was wrong to laugh at the joke, and one of those reasons (probably the least-focused-on reason of the conversation) was the fact that it can belittle trans men who have small hands. There was probably an "also" at the beginning of the sentence, or a "too" at the end of it. But the author went into the conversation with an attitude, and they and latched onto that one reason because, when presented as the sole reason, it sounds ridiculous. But it's not the sole reason, more like one example of the effects of the same thing: belittling people.

The title should be I used to be able to pretend to be a good person, but now it takes too much effort because I actually have to put a little thought into social interactions instead of just mindlessly treating people the way I was trained to.

I assume this all boils down to laziness on the author's part. They aren't a bad person per-se, they just don't feel like putting effort into being a good person. This is folly, however, because in not trying to be a good person, one ignorantly allows themselves to do bad things without realizing or caring.

I grew up in the right-wingest redneckest parts of the Appalachian hollers, and it has taken exactly no time at all for me and others to learn how to treat people right after learning about hierarchy and exploitation, even after a lifetime of right-wing brainwashing. And I didn't get converted by people, I got here by seeing people suffer and deciding not to contribute to that suffering as much as I am able. Nobody had to tell me not to marginalize people. I cannot be convinced that, after being taught by their friends about this stuff, a good person wouldn't make it their sole goal to improve. Only lazy inconsiderate people complain the way this post complains.