It's likely the reason they don't feel embarrassment is because they couldn't care less about your unwarranted judgement, and delight knowing that some people actually take the time to be upset about it.
This always comes up in these discussions, my impression is that there is some kind of a split when it comes to understanding the concept of embarrassment. It is not about the individual judgement of people and being upset is the wrong word, but it is difficult to find the right words to explain it. When thinking to myself why I'd never do these kinds of things, setting aside the lack of interest, I wouldn't want a kind of general perception that people have of me to be associated with these cultural symbols. It is an interesting question, especially because it appears obvious until I reflect on it. I guess I am not the only one who feels like this, and some people get upset because it is difficult to articulate these "unwritten rules of behaviour in polite society".
To me it's sad that you took that lesson away from that. :(
Watching someone be genuinely enthusiastic about something is wonderful. Society has far too much cynicism, and watching it beat that into children as they grow up is no fun. I see a lot of adults who treat things that way.
Maybe it's a generational thing, maybe it's my circles, but I've seen plenty people appreciating and gushing about people sharing their interests. It's even in the memes, here's an example:
> Everyone wants an autistic gf who infodumps abt video games and linguistics and whatever up until day 43 of the relationship when you get a paper cut and she starts trying to drink your blood
> Watching someone be genuinely enthusiastic about something is wonderful.
But isn't the question what they are being enthusiastic about? I would certiainly agree that there are some things that considered noble and respectable (helping the sick, science, the right kind of activism for the right kind of people, ...) that most admire. At the same time I think most recognize that there are destructive or non-productive things one can be enthusiastic about to the point of obsession. While having an anime girl on your website or being a furry is usually not destructive and ignore the cultural popular images of people like these, then they are at least non-productive in the sense that neither society nor the individual themselves grows from engaging with the topic. You can study engineering and improve human technology or write and learn how to better express yourself, but I don't see how anyone can progress as an anime weeaboo beyond a self-contained culture that might value if you know the names and details of all characters by heart. As soon as you step out of this bubble, the value disappears.
> Maybe it's a generational thing, maybe it's my circles, but I've seen plenty people appreciating and gushing about people sharing their interests.
I don't know what generation you are referring too. I'm Gen Z and obviously have different feelings about this. Sure, I enjoy talking to people who share my interests, but I know when and where the right place is. I don't go out with friends and insist on talking about e.g. Emacs, and I certainly don't want to be perceived as someone who superficially is only interested in my own topics, not caring to engage with topics that others care about.
(Btw. thank for your respectful tone, I appreciate that).