"Everyone can draw their own conclusions as to what’s causing this." - Trump caused this. It's clear and simple.
And a whole contingent of Americans who don't seem to recognize this as a serious diplomatic concern. Look at the bulk of comments in this post trying to handwave this away as some kind of "trade dispute" or "irrational fear of ICE" or "Canadian dollar is low."
No, your president and his entire cabinet say they're going to annex our country. Gee, I wonder why we wouldn't travel there.
Pretty sure the GOP is just Trump MAGA now. Not sure who, if any, the holdouts are now.
Hence the famous quip by the Fox News host to Doug Ford that he was "offended" or surprised that Canadians wouldn't want to be part of the US.
To many, I suspect, "51st state" was supposed to be some kind of compliment or favourable invitation.