> One can hardly see how the trucker protests qualify as such

There are multiple facets to the protests.

- Blocking the bridge that was responsible for a sizeable percentage of trade between US and Canada goes far beyond a protest and any government would be well within their right to classify this as an emergency.

- You had US-based, armed, ultra-right wing militia elements who weren't trying to protest at all but rather sow discord. These were the types wanting to overthrow the government. Which meant that police weren't able to control the situation and there were legitimate concerns about it getting out of hand.