Mike,
As I view it, once guys like Colin Morikawa, Rory, and other high level players came out in LA saying they were all against it, I think that's when the others fell in line due to whatever reason. Its possible Phil and BDC really were on the fence, and just waiting for other high profile guys to chime in to see which way it was going to go.
P.S. The problem with Phil in practical terms is, he'll be 52 in a few months, he's basically done, even if he could play on the PGA Tour for as long as he wants. So him chiming in wasn't going to accomplish anything, and its plausible he had some backdoor deal with Norman to fan the flames in exchange for a higher sign on bonus.