A part of being grown up is about being realistic about things.
But realistic does not mean focusing on the bad stuff any more than it means focusing on the good.
If you're really so Grown Up, go and do something worthwhile. Apply your superior analytical skills for a job or a cause or something constructive instead of picking on children on the internet.
Yes, people take things too far, but making fun of them is not clever or funny. It's destructive. It's not your job to tell people how to use a website or how to express themselves.
And while we're on the subject, saying you just don't care about something in a discussion about it is incredibly puerile. You shut down the conversation and make someone feel guilty for liking things.
You can not care about people on the internet, or people in your neighbourhood, or about anything except yourself and your keyboard, but that doesn't make you somehow superior to everyone who cares.
Especially if someone's clearly passionate about something and trying to enthuse you- you can say it politely of course, but put in some effort.
Argh. I thought I was done with this after high school when people would say "well I don't really care anyway" when they didn't understand philosophical points. Well done, applause for you, you have won.
You have been incredibly rude and wasted everybody's time. Move on to a new subject if you think you can't contribute about something, but do it gently.
And before anyone asks why you should care about other people's feelings, which is a horrible question in itself (when did we learn hurting others was okay?), there is literature on this.
There are plenty of theories, whole philosophies, based on the idea of why happiness is important, and why caring for others will ultimately lead to good things.
Isn't it just logical to universalise? If nobody cared about others, if everyone treated others like shit and didn't care, the world we live in would be messed up. We would suffer more.
We all have a responsibility to contribute to the general wealth of human happiness because the things we're angry about could be changed if we all tackled them together.
We all have a responsibility to support other humans because that gives us the right to expect support in turn.
We should respect each other because it is so much better to love than to hate.
Not caring and being cynical don't make you instantly more grown up. They make you a jackass. So shut up, get off your high horse, stop bullying people, and read some fucking Aristotle.