Matt Yglesias has been on this kick, most recently in this post on Hugo Chavez and his weird paeon to Idi Amin (among others), of citing to a Human Rights Watch report on the country in question, then sarcastically dismissing it with something like "but everyone knows that HRW is a non-credible group obsessed with unfair slams on Israel so their criticism of Chavez must somehow be part of their vast conspiracy."
This annoys me. But not for the reason you think! Rather, it's because I think the jibe isn't quite on target. The point of Matt's critique is to make fun of pro-Israel writers who have been busy savaging HRW as an anti-Israel organization due to its various critiques of Israeli policy. But I don't think that this has converged with any desire to discredit HRW reports on other countries. Much the opposite -- a major facet of the critique has been a supposed lack of equitable attention given to these countries.
Meanwhile, the point of Matt's HRW defense is that they suspect that HRW is being attacked not because of any substantive errors in their analysis, but based off the simple syllogism of critiquing Israel = prejudicially anti-Israel. Which means the analogous "joke" with regards to Venezuela or wherever would be to say something like "I guess this is yet another manifestation of HRW's anti-Venezuela bias", or something to that effect. That would more accurately represent the objection, that "bias" here simply means "you criticized the country", rather than stretching to try and tie anti-HRW Israelphiles' attacks into something beyond just HRW and Israel.