I don't think Randy was trying to start rumors; I think that all he was getting at is just that for most mutations, we don't know what, on a chemical level, is really going on to cause the aberrant pattern that we see and breed for. For all we know, whatever mutation causes the unusual color or pattern could also cause a problem with fertility.
Do I think that most of them will be infertile or subfertile? No, not at all. So far, I can only think of two out of the dozens of morphs that have seemingly substantiated reports of fertility issues. I certainly don't think it would stop me from investing in a new morph if I thought it was promising. But it is always a possibility (just as it's always a possibility that the homozygous form will be lethal, or that there will be some other defect associated with the desirable morph gene).
I think it all depends on how you look at it -- just like you can look at an unproven morph or dinker as "It isn't a morph until it's proven" or, the more optimistic outlook, "It isn't a normal until proven normal," you can look at any new morph as "It isn't fertile until proven fertile" or "It isn't infertile until proven infertile." Glass is either half empty or half full type of thing.