What is the rationale behind placing 2nd stage evolutions in gyms?

Not that it matters a whole lot but I see this behaviour all the time and it really confuses me. Why do some people put the 2nd stage of a 3 stage evolutions in gyms?

I get it if they put the first stage evolution (e.g. Dratini, Oddish, whatever), they want to save potions and be selfish and just collect coins, or are just trolling.

I get it when they put final evolutions like dragonite, because they want to defend.

But what about stuff like wartortle, ivysaur? Why do people put them in gyms lol? They don't defend well, they are terrible to prestige with, and tbh it is worse than leaving a Pidgey or magikarp in, at least you can beat those fairly quickly. Some people just want to watch the world burn?