perhaps. but i just like to point out that some inbred populations (namely where i am originally from) such as sardinia have had surprising results. According to a BBC article about places where people live the longest (and i quote):
In Ovodda (Sardinia), this interbreeding actually seems to have enabled people to live longer. The limited gene pool has provided a unique opportunity to discover specific genes that are associated with long life. Professor Deiana has detected a number of unusual genetic characteristics that seem to link the centenarians of Ovodda.
"One particular gene on the X chromosome seems to be faulty, failing to produce an enzyme known as G6PD. This can often have a negative impact on health, but in Ovodda it may well have had a positive effect."
The role G6PD may play in living longer is now being researched further, but the professor is convinced the genetic elixir of life lies with the families of Ovodda.
unquote. so a tiny fraction of inbreeding apparently has positive effects (and i do only say tiny fraction!!!)