There are several arguments.
The first (relevant one):
Why not have seasonal forms? (discussion prompt)
Why have seasonal forms? (contributer1 asks OP to convince him with further evidence)
Why didn't you ask that about the other seasonal things? (contributer2 needs more convincing of contributer1's dispute, and asks contributer1 to provide supporting evidence of his claims)
You don't have to be angry to have an argument. That's just what your parents. Actually arguments are much better when you're not angry or annoyed. So why are you so annoyed?
Gee whillickers what am I saying. I'm -sorry- I asked someone to back up an idea with evidence on a discussion board, Frosty.
(Now, it's your turn. You say you're sorry.)