Comment by AnimalMuppet

I think it's like this. People think differently. Someone finds a language that really fits the way they think, and it feels wonderful, and they feel like they've been let out of prison into this wonderful new freedom. And they, being empathetic humans, want other people to have the same experience, and they think that others will have the same experience if they just try this wonderful language. So they become language missionaries.

But what they miss is that other people think differently than them. Other people will feel let out of prison by a different language.