They are not saying "we the firm support SOPA" but they are saying "our lawyer looked at this law for our client and he finds it constitutional though this is not the position of the entire firm." I can understand if you're not disturbed by the latter but I think a simple incentive analysis should make it clear why I'm not the first to argue against sharing law firms with those on the opposite sides of controversial issues facing the court.
A simple hypothetical should explain it: ESPN wants SOPA, they get their lawyer to sign a letter which says the law looks fine. Let's say the law threatens the startup's business at the same time, maybe the law firm isn't as likely to write or sign a letter arguing against the law if it means it upsets ESPN. End result, more lawyers at these firms sign on to SOPA and you end up with what appears like considerably more support for that side from the legal community simply b/c bigger clients support the law than those that oppose it.
Really -- my point is simply that you don't need to hire a 5000 lawyer firm who also represents ESPN & the NFL when a 20 lawyer firm will do. I believe that is in line with the startup ethic as well.
And again that's not my point at all to not work with lawyers who work with murderers -- your statement of my position is a straw man at best and a dishonest mischaracterization at worst. I'm not saying ESPN did anything wrong here -- I'm saying ESPN disagrees with your startup's positions and it is paying that law firm to do what it can to win and hold their position. Maybe it's not a good idea to hire the firm if you don't like the law, you know?