I think he's liked and retracted before, but I suspect JKR's tenacity and calm poise might be giving a bit of courage to all sorts of people who, for whatever reason, have been intimidated into silence. Of course it was disappointing to see that she didn't get immediate and fulsome support, but by not backing down herself (because why would she?) she has trailblazed so that others can see that actually, you don't burst into flames if you hold the line, and there is safety in numbers.
Essentially, JKR is the bigger name's and wider public's Spartacus moment. You don't break a dam by pushing it once, you need to apply consistent pressure. It's the same with a wall of silence. I see JKR very much as an honorary denizen of FWR, speaking out and getting shit just because we know it's going to take dedication. (And honestly, if she's not here already, I think I'll be very surprised...)