These aren't just employees who signed these letters independently. They were asked by a client to sign onto the letter which agrees with the clients interests. They sign these precisely because the client of the firm paid them to. While I was at a firm we signed onto letters or drafted our own for clients all the time (and it was precisely b/c it helped get the laws through, so call it what you want -- i know I don't mind "support" though I can see how some object to the technicality). In laymen's terms, client shows up and says "we need this law to go through we'd like to hire a lawyer to write an independent legal opinion letter to the court to help them make their decision. Or maybe you guys can sign on to this guy's already written letter? We'll pay you for it, of course."

The techdirt article points this out too. When there's a law up for debate which a client wants to get through they try to get these letters in to make it more likely the law will pass. And yes this is different from official "support" which is saying "we the law firm want this law to pass." This is more like "our lawyer looked at this for our client and he does not think it's unconstitutional though this is not the position of the entire firm." To me, that's still bad but I completely understand if others are okay with it. Reasonable men can and do disagree about a lot of things.