This attack has many benefits for leftists:
1. Equate white Christians with Muslim terrorists
2. Gun control.
3. Counterbalance the memory of the videos
4. Damage pro-lifers.
Too good to pass up?
Fight back.
Point out that decent folk decry murder no matter who commits it.
Liberals are hypocrites.
They rave against madmen who shoot up Planned Parenthood, but have no problem with the Planned Parenthood mass murderers themselves.