It is insane. Is there any person who can just turn their emotions off on command.

Yes, most people can hear the words "calm down" and not freak the fuck out over it. In fact, if those two words really do set you off, then chances are you weren't actually nearly as calm as you're claiming.

With reasonable people, when you tell them to chill out, they usually just chill out a bit. It's a pretty Karen move to freak out and use that as your justification for freaking out, so I'm not sure why Reddit loves the idea so much.

Like seriously, people tell you that they think you're acting too aggressively and so your answer to that is to get all upset and act more aggressively? Grow up.