Two phrases---"Earth Liberation Front" and "Animal Liberation Front". Now, tell me again about "stereotyping".
I've watched the eco-nutcases in action for forty years, I know what they are all about.
...then "pro-life" activists are all like Eric Rudolph. Every activist group has its extreme militants. You cannot characterize the entire movement by the extremist factions.
Otherwise:
All muslims are terrorists.
All WASPs are KKK members.
All priests are pedophiles.
All American soldiers take pleasure in the sexual abuse of others (a la Abu Ghuraib).
and so on.
"Do unto others as you would have them done unto you."
We will get nowhere if we are considered women-hating, zionist, radical Christian doctor-killers. So we certainly do not want to stereotype other groups by the extreme actions a few professed members.