I think it tends to always happen with greater frequency from the party that is not in power. Conservative republicans are in power and control the major political offices, therefore the liberal radicals have less a stake in society, less to lose, and more to gain by opposing the status quo. While things are like this you'll hear more from the Louis Farakhans and Peta.
When the liberal democrats sweep into power, you'll see more bombing of abortion clinics, and beating of gay people to death.
It's sort of cyclic.