I know I am repeating myself, but it appears to be necessary. The vast majority of ERV and ERV remnants that can be found in human and chimp genomes are to be found in precisely corresponding locations in the DNA of each species. As the integrase enzyme that - um - integrates retroviral DNA into the host genome cannot target specific loci, to believe that the commonality of location among all these elements is a coincidence
is beyond the bounds of credibility. That a relatively small number of ERV elements are unique to chimps or unique to humans can be easily explained by post-speciation endogenizations, or (less easy to comprehend but nevertheless a real phenomenon), incomplete lineage sorting where a preintegration site goes to fixation in one species, but the postintegration site goes to fixation in the other.
And here again is my link that explains how we can be confident that an ERV is the inherited result of a retroviral integration.
Veritas: ERV FAQ: Why do virologists and geneticists think that ERVs come from retroviruses? Isn't that just supposition on their part?