I'm late to the thread, but I have a unique perspective / this is a matter of significant personal interest to me, so....
The negative test requirement is stupid. Even stupider that it can't be a rapid test (but I do agree with the vaccine requirement). It's a good first step at least and WAY overdue.
The vaccines are not 100% effective at preventing infection/contagion. There are enough breakthrough cases for the testing requirement to be reasonable until enough people are vaccinated for the disease to settle down to its eventual endemic level.
(My wife and I are currently positive, despite both of us having been fully vaccinated, and my having had COVID last fall. She's got the symptoms of a bad cold. I've got a sniffle and some aches that aren't as bad as the vaccine side effects.)
That being said, the hassle of having to take a COVID test before crossing may mean that I go up less frequently. I still need to research the particulars of filling prescriptions while visiting Canada and bringing the meds back to the US; a couple of prescriptions I was put on in the past couple of months would be less hideously expensive at the pharmacy across the street from my office than the pharmacy we use down here.
Politics aside, the arrogant attitude a lot of Canadians have towards American tourists in general (which has worsened since COVID) has really left a sour taste in my mouth.
I have relatives that live in the Detroit suburbs and they stopped going over before Covid broke out because of that.
Former WWE wrestler Bob Holly also wrote this in his book about going to Canada:
Montreal is completely the opposite of Australia---there seems to be a lot of rude people in Montreal. Several times when I stopped to ask for directions, the French Canadians just looked at me funny and walked off. I never did like going into Canada, period. Not many of the boys did. It was always such a hassle at customs. We entered other countries without a problem, but getting into Canada could be brutal. They'd take forever with us; it was torture. Any time we worked there, we'd get paid in Canadian dollars, so when the exchange rate was bad, we lost money like crazy. You'd better believe that seeing Canada on the schedule was a real buzzkill.
My current job is based in Montréal, despite my living in Connecticut.
My experience has been completely different. Wonderful people, great food....but you do have to respect the culture, and collectively Americans generally do a lousy job of that. Language is essentially a civil rights thing in Québec. But learning how to apologetically say, "Pardon, je suis American/Americanne. Je ne pas parlez francais" goes a very long way to smoothing things over with Québecois francophones.
I'll admit that there are a few things that the Québec national government (and conversationally recognizing it as a national government and not just a provincial government is part of respecting the culture) does that I disagree with...but I'm a visitor and avoid getting involved beyond the extent necessary for my job.
Heck, part of the intriguing part of my socializing with my Canadian coworkers is coming to realize how much of the fundaments behind my political stances rely on assumptions that don't necessarily translate north of the border...and I won't go into detail on that point due to the rules of the forum.
