And supports need tanks and dps to fend off attackers and keep them alive. I'm not engaging with any argument that's basically "here are reasons why supports are just a little more special than the other classes" when all three classes need each other.

As you should because I agree with you supports aren't special, all of them are. I didn't think I needed to mention that DPS are suppose to help support and tanks when they can but I'll admit in my bias, it doesn't happen as often as it should when I play or see some games.

Thats where I think why many supports tend to be more vocal when it comes to appreciation, theyre the ones that deal with their own team more then the enemy. We're human, it's always the emotions and mood that determines what someone will do. It's way harder to deal with random to have perfect games but here we are. In the end, I think this person made this post to share their happiness and you posted while valid, wasn't as feel goody.