Yes everything in mogstation is really expensive for what they are.

But they're selling them at that price because a lot of players still buy the stuff. Paying 5 dollars for an emote that isn't even account wide is ludicrous. But again, people buy them. And so many people pay for the mogstation items that SE keeps adding more and more to it at high prices.
So don't blame SE for this. Blame people who pay for it. But then you'd be trying to tell people how to spend their spare money, which no one likes.