The issue with that is, by the time the US liquor is sitting on the shelf for sale the US producers already got paid. The liquor is first bought by provincial distributors, even in Alberta via the AGLC, and then sold to the public from government stores, or sold to private liquor stores who then sell to the public. So if that US liquor hits the shelf and we boycott it, it's either our provincial governments or local liquor stores that take the hit. That's why the provincial level bans are angering the US liquor industry so much.

Appeasing the US by allowing their alcohol back on the shelves

Except that we should have learned by now that trying to appease a country who won't honour their own agreements is pointless.

What guarantees can there be that the US won't just reneg again after we appease them again?

They should have to demonstrate some level of trustworthiness before we even think about backing down.