IANAL, but this doesn't sound quite right. I think they need to be able to show mens rea on your part, that is, that you actually believed the person might commit murder and deliberately helped them.
if you agree with my nitpick, then all of your examples show a clear intention to incite others to do specific material harm.
on the other hand, if someone says "X group doesn't deserve to live", it's hard to say whether they are deliberately inciting violence. if X is saints fans, you might reasonably assume the person is joking. if X is a marginalized group, it's still hard to say whether it's an incitement of violence or a gross opinion that lacks actual intent to incite violence. if it were easy to show that it was a deliberate incitement of violence, then it would already be illegal under current laws.
False, see Anarchist's cookbook and similar cases such as MIT's lockpicking guide
> If I rouse a group of people into flipping over cars, breaking windows, and hurling rocks at the police, I'll be charged with incitement
Incitement is a crime. It requires specific, actionable intent. "Screw the police" is not incitement, "go hang group X" is.
> If I yell fire in a crowded theater
Not a crime
> If I con the police into arresting you for something you didn't do
That's making a false statement to police
> If all of that is criminal, then it's not much of a stretch to include escalation to hate crimes as a prosecutable offense
Thank goodness it's not
If I describe to you exactly how you might go about murdering someone, and they get murdered, I'm likely to be a suspect, and if you're charged, I'll be charged as an accessory. If I rouse a group of people into flipping over cars, breaking windows, and hurling rocks at the police, I'll be charged with incitement. If I yell fire in a crowded theater... I can't recall what the charge is but it's not good (endangerment?). If I con the police into arresting you for something you didn't do, I can be charged for that as well (and you probably ought to also sue me for civil penalties).
If all of that is criminal, then it's not much of a stretch to include escalation to hate crimes as a prosecutable offense. Grooming people toward these activities might be a grey area, but it's a grey area, not an unassailable one.