It seems like a really minor point to be so staunchly "old school" about. There's no harm in it. Could someone potentially cause harm to their snake by tightly tying or gluing some weird hat onto their snake's head? I suppose so...but such a person is probably causing all sorts of harm to their animal anyhow, and a few cute pictures of snakes wearing hats (or the absence of such pictures) isn't going to change that.
Really, there's so little potential for true harm. In my opinion, there IS plenty of potential for good to come of it. How many people who are reluctant to like, or are indifferent to snakes are turned around by pictures that make the animals look particularly cute, friendly, and/or something they can relate to? Would they win over staunch haters who kill every snake they encounter? Probably not...but even then, who can say?
I don't think everyone needs to rush out and make hats for their snakes and try to convince the snakes that wearing them is "fun"...but for the few people that do, and manage to get fun pictures...why not?