The thing with politicians is that it is in their nature to be opportunistic. When their popularity drops, their preparedness to talk out of their backside increases. Quite a simple equation, really.
Then there is that other phenomenon, best characterised by bandwagon-jumping. Once an issue appears to be safe to populate with general outcries of self-righteous babble, myriads of morons join the party and jump up and down like five-year-olds who have discovered the trampoline.