But before they actually commit a crime against someone, the Shawna Fordes of the world haven't violated any laws. You can't criminalize someone for their words alone, that's providing legal precedent for thoughtcrime.
Well, first, yes, they have, they obviously discussed their plan beforehand, that's conspiracy, illegal many places, United States and Canada as well, likely as well in your country if you're from somewhere else. As to thought crime, well, yes, there is certainly something to be concerned about, personally in our Charter I would have preferred the right to opinion somewhere it didn't fall under those legal limits, but as in our Charter the right to opinion is different from from the right to expression, so their curtailments can be set at different thresholds. This can once more be limited to what is right in a free and democratic society.
EDIT: since you brought up conspiracy to murder- if there are people publicly calling for someone's death as well as conspiring to kill them, they still haven't committed a crime until they actually attempt to kill them. And if a conspiracy to kill someone is that well known, (well known enough for the law to even be able to intervene) then it's not a very good conspiracy. Conspiracies for murder only work if there is very little public speech against the target.
Again, they've committed a crime. Yes, no one has yet been affected at this stage, but if I see a glass drop, I'll catch it before it shatters, not pick up the pieces. Conspiracy doesn't need to be well know to get out (perhaps the people that threw Shawna out of their organization for being unstable might have said something discrete to the police) and again, it's a different beast than hate speech. But you seem to be taking the stronger position (as in it almost entails the weaker position that hate speech oughtn't be a crime) that conspiracy oughtn't be a crime, so I think we'll deal with this issue first.
And with regards to the whole "I would never defend the WBC" issue, I feel it's necessary to make something clear: No one has a right to not be offended. The Westboro Baptist Church may say hateful, offensive things. But they are entirely allowed to be offensive. That's the flipside to Freedom of Speech: you make everything positive, thoughtful and righteous to say legal as well as everything negative, cruel and stupid. You can't have one without the other.
I'm with you halfway here. I can't say that the WBC likely poses much of a threat with what they do, so yeah, not interested in limiting what they say. But I don't see how you need to have cruelty to have righteousness. The world isn't a zero sum game.