They already did it to GWB. Remember the Bush is Hitler signs, Re-defeat Bush signs, leftists crashing the 2004 RNC convention. Cindy Sheehan sitting on his property demanding to speak to him when he already spoke to her before.
They're just pissed that people are fighting back and supporting a candidate who won't put up with this crap anymore.
And that idiot Bush just sat there and took it, which emboldened them ever more.