when they say "left wing extremist" ...

[writerspleasure.livejournal.com]

is used no more than "right wing extremist," show them this, from the wonderful http://ngrams.googlelabs.com/:



try running these - for some reason i can only post up a single graph:

in an interesting shift, with the beginning stir of right-wing opposition to left-wing bias:
left%20wing%20extremism,right%20wing%20extremism

very interesting:
left%20wing,right%20wing

progressive spikes:
greedy%20capitalist

run your own and show the results!