It's actually in the video you posted so I've seen it. They were there with masks, they were not protesting, but they were standing peacefully: that is what I see in the video.
> The Canadian police got caught out trying to incite things
That's why I was talking about the "rock in their hands" part of the story because that's the only part that would be valuable at all to support the claim that they were there to "incite".
But actually you're probably wondering about the reason why they are dressed like other violent protesters (which we can see in an earlier part of the video in another street), there's a reason for that, and it's pretty simple: it makes it easier to catch them. And when you do you're burned so it's not like the costume is going to last forever.
Why did they then go to the peaceful street then? Because they were expecting the violent protesters from the other street to refuge there and take off their masks and blend in with the peaceful protesters. By being there first they could have caught them, but the "peaceful protestors" who "caught them" didn't let them do their job.
I don't believe one second that they did that to incite things, that they would be throwing rocks at their own colleagues, and have seen absolutely no reason let alone any evidence to think otherwise.
But even if their presence did incite you, then you would get caught extremely fast, and that would probably be a better ending for everybody including yourself, before you become a bigger danger.