"...the total number of new mutations per diploid human genome per generation is about 100...at least 10% of these are deletereous...analysis of human variability suggtsthat a normal person carries thousands of deletereous alleles..."<quoted text>
There is no such thing as genetic entropy. Therefore, it cannot be the cause of any natural phenomena.
The problems that arise from incest are not genetic entropy.
S. Kondrashov. 2002. Direct estimates of human per nucleotide mutation rates at 20 loci causing Mendelian diseases. Human Mutations.
Then what are the problems with incest and recessive genes if it's not the accumulation of VSDMs? This is exactly what the problem is.