No argument here. There's enough acrimony between a small but vocal portion of the two companies' fan bases as it is. Doesn't really need additional stirring up, even as a "joke."
I guess you guys didn't see the Paizo homepage today. Look in the upper left-hand corner for the "d21" logo and read their latest news announcement. This was obviously a team effort. If you're going to hate WotC for this, you're going to have to put Paizo over your knee, as well.
I don't know. It seems that they caught at least three people with their pants down. Or. . . maybe it wasn't a team effort and Paizo caught a whole lot of people at WotC with their pants down