I assume that they are doing what they feel the Lord is leading them to do.
Why should we question that or expect us to be able to decide how many is
enough. When I was a YEC I was clearly on the wrong track, but God lead me
down paths I never expected to go. Should I not have been involved as a
YEC? I would say yes, because if I had never been a YEC, I would not be
what I am today [an obnoxious, argumentative, persistent, SOB :-) ]
But the point is, it is not up to you or I to decide how many is enough.
Foundation, Fall and Flood
Adam, Apes and Anthropology
Lots of information on creation/evolution