The best way to hurt a cause is to make a poor argument in its defence.
The sheer bulk of frankly stupid arguments used in favour of creationism do not help its image in the slightest. If its proponents seem dim witted and uneducated then the cause loses any credibility it has in the eyes of an observer.
This is a fairly universal problem however. I have seen arguments evolution/old earth that are just as poorly thought through as the worst creationist arguments and must only help to convince creationists the mainstream ideas are wrong.