Yeah, that's a legit question. While things are still TBD, my answer is that in this case, it's not just low heights over AK, but the aleutian high is getting broken down with lower heights over the aleutians. This leads to a +PNA ridge over the west. If you animate that run from 300-360, you'll see the +PNA ridge building. Plus with that ridge, that extremely cold air over AK/Yukon will get shoved SE towards the eastern US albeit with some modification.
Imagine instead if the aleutian high stayed, and the AK vortex helps dig a trough over the west, then yes that would be bad. But the models aren't showing that.