There is one factor that we (the supporters of science in general and evolution in particular) tend to forget. The majority of 'creationists' I debate on the internet are, i think, not creationists at all. Many of them are just trolls. Those I would subdivide into contrarians and social. The social troll is someone for whom the internet is their social life. There are many examples of this type of poster on all messageboards. They crave attention and are willing to support any notion just to get attention. The fact that the majority of attention is negative doesn't matter, they just want to know that they are still alive by getting some sort of response. I suspect the psychology many be similar to that of many self-harmers, but that is way out of my area of expertise so I'll not develop it here. The contrarian troll is similar but the basic motivation is to attack what they see as any cosy consensus. This type of troll often sees themself as a brave defender of individualist thought and freedom against a mass of conformist robots. They commonly post on climate science but are also found attacking any established theory or commonly held point of view.
I submit that neither of these two groups are creationists in the sense of starting with a deep belief which they are compelled to defend. It could be that either type would eventually persuade themselves of the 'truth' of creationism, but I doubt many do.