I think chc's point is that it takes less time to google "Cornyn Guantanamo" and "Cornyn wiretapping" than it does to post the question here, and will produce a better answer to boot.
In this case its valid. Yes we can google it, everyone here knows how to do that. The bigger problem is knowing from where people got their information.
A Senator's stances on issues like these are simple, objective, easily falsifiable facts. This is one or two steps away from demanding a citation for "Barack Obama is a Democrat." Like, if you can't easily figure out for yourself whether it's true or false, the only possible reason is that you didn't care enough to try.