In my personal experience, most creationist posters that come here have a quite narrow focus. They usually have one or a small number of issues that they really want to talk about.
This might be 'law and origins and purpose', 'whale evolution', 'haeckel's fraud', 'biblical prohecy', or 'biblical archaelogy'.
If I'm being kind, then I'd suggest that they start fine. They'll find a relevant thread or make a PNT on their favourite subject. The one that drove them to register. Their argument is almost immediately descended upon by 'evolutionists', keen to take on some fresh debater.
At this point, some simply give up and leave. They might rationalize it by referring to the hostility they received or the terrible moderation. But one way or another, they don't want to stick around.
Some stay, they air some of their other focuses.
But then trouble starts to brew. They begin to repeat themselves. At first its in the appropriate threads. Its as if all those refutations had never been written. When people react angrily to this, the creationists react angrily back - usually but not always, escalating things beyond any acceptable level.
That's their first set of suspensions.
But then they start to bring their favoured line of arguments into threads where it is off topic. They react to criticism of this by ramping up the invective. This is their second set of suspensions.
Usually that's sufficient to invoke voluntary exile from EvC. Some stick around, but after a few rounds of the above, they soon leave.
Some of the longer term creationists have been through this cycle numerous times, but I think breadth of interest helps tremendously. Buz, for example, has his favoured subjects of course, but he dabbles in other topics too.
There may be some creationist lurkers though, I guess. They may be deterred by the perceived treatment of those that take the step of posting in a thread.
There is another effect, that comes into many communities:
Earn Your Bullshit. Longstanding members tend to get more leeway as they are community mates, possibly verging on friends. And since most longstanding members are evolutionists... This effects creationists too - people complained about Faith's indefinite suspension, and I think they would if Buz received the same.
I feel sorry for the creationists, but not too much. I've managed to stick mostly within the rules for my duration here, so I know it isn't difficult. But maybe the creationists are being hard done by. It's not difficult to see why people who think something like 'fuck you' (such as in
Message 229) is acceptable might get suspended. But maybe there really is a terrible culture at work that I'm blind to. I would like for any creationist that has a genuine problem with a poster, to alert the moderators to it in the thread we have specifically designed for that purpose. We might well disagree that a problem exists, but at least you'll be doing the right thing - and it will be on the record (perfect for citing evidence later). The correct way to handle an abusive or disruptive poster is not to become more abusive and disruptive than they are. That will result in suspensions if its seen.
Finally, I agree with Percy. There is no shortage of creationists, so there should be no shortage of creationist posters. While the perception around here may deter some, the fact is that most creationists aren't really thinking about it enough in their lives to start looking for forums to post in. Without it being in the news, its in the back of their minds. Evolutionists on the other hand, are aware that creationism is still a threat that deserves at least some consistent attention.
A good number of creationists these days seem more concerned with discrediting atheism. So if they're going to sign up somewhere 'hostile' to argue their points, it'll be a skeptics or atheist website/twitter feed.