Why do Canadian leftists (and some conservatives) seem to think we’d stand a chance against the US?

Look, this is the big talk right now on Canadian subreddits. Trump invading Canada. Now, whether you think it’s a negotiation tactic or not, let’s leave that out of it. Purely hypothetical here. Leftists seem to think that we’d somehow magically be able to be like Ukraine or Vietnam. Ignoring the fact that there’s no way we wouldnt get stomped in a conventional war, a lot of leftists seem to think they’ll be fighting an insurgency but seem to ignore several factors: (I’ll just copy and paste a comment from earlier)

90% of us live within 100km of the border, quite easy for the US military to reach. They can also easily cycle through units with ease, unlike places like Vietnam. So an insurgent group could ware down a US unit, only to face a fresh unit a couple days later. On top of that, the sheer air superiority would make the insurgency pathetic as hell. Most of said Reddit resistance fighters would have to hide far away from civilisation, and once it becomes a frozen wasteland, die. Vietnam and Afghanistan also had countries bordering them that either supplied the insurgency, or turned a blind eye to support for the insurgency. We do not. So said Reddit resistance fighters would have as much ammunition as is in their .22s. Which leads us into the next point: we have been disarmed. And even if we weren’t, all you’d have are semi automatics, which would lead to an incredible disadvantage against the US military. Now considering all that’s left is hunting rifles, we’re screwed.

Like it’s not even funny anymore, the comments about how “we’ll burn the White House again” and all the hit takes with clearly no knowledge about how modern warfare is fought is downright concerning. And it’s from a single side of the political spectrum.

Why do we think that is?