I think they are just poor creatures. They may look a bit ugly, but if anyone has a creeper skin doesn't mean that they are mean, or am I wrong?
Creepers maybe don't want to explode. Maybe it's just an natural instinct of them.
This picture should show you that creepers have feelings too, they are just creatures like any other ones too (pigs, birds, sheep,.....)
Maybe it's just me that thinks so, but I don't think that I'm the only one
