This was totally the right move, if for no other reason than it's the only thing that this US admin will respect in the long run. Being in Canada though this does look v. short sighted of the US. All this is going to achieve is pushing Canada much closer to other countries, particularly China, which at least superficially these negotiations were meant to prevent.
Unfortunately, Canada (where I live) will feel way more pain from this than the US. I am not sure Trump will have respect for this at all, but the alternative was to put in a permanent trade deal that significant disadvantaged Canada.