Why do people call it preaching?

I was expecting something like “some just mention it and move on”. Instead…

It’s baffling that “Hey maybe hamburgers aren’t worth kilometers of cows chained with their face in a feed trough. Arranged this way so that the only activity they can engage in is to gorge themselves on low quality feed frequently filled with bits of other cows (backfeeding). Maybe they like have feelings and deserve better than this followed by a dehydrated wait in a death line in some artificially lit temple to screams and blood and horror?”

lol