I don't have a Youtube account, but a few simple ideas you can counter with:
1. XMRV has not been proven to be a lab contaminant. Contamination has been suggested as a possible explanation, but it has hardly been proven.
2. The contamination theory doesn't even begin to explain most of the existing evidence. It cannot account for antibody responses, nor can it account for viral proteins, nor can it account for consistently higher positivity rates in patients than controls (under blinded conditions). It cannot account for the genetic diversity of HGRVs found in the WPI and Lo/Alter papers and their subsequent findings. It cannot explain proviral integration unless one squints really hard and stretches his/her gullibility to the breaking point. Any theory that fails to address over half of the data (and addresses the little it does pertain to in an inconsistent, patchwork manner) is not only not proven but likely dead on arrival.
3. The poster says: "And XMRV is not a human retrovirus. Notice the other two: Hiv and Htlv both have H in? them which stands for Human." This is beyond inane. It is like suggesting that a viper is no longer dangerous if one calls it a bunny instead. It's not even an argument, it's just playing (really obvious) sleight of hand with words.
4. The poster says: "It is still unclear what causes CFS/ME but it is not XMRV.?" This is another example of the current denialist mantra: Anything but XMRV. Apparently, everything about ME/CFS is a huge amorphous mystery, except that the denialists know with absolute certainty that XMRV is not involved. Says the denialist: Ignore the man behind the curtain!
