Russia has been trying to destabilize western democracies in general through this kind of indirect manipulations for a while because the liberal democracy model threatens its authoritarian regime. Other examples are Russia helping anti-EU far right parties, Wagner mercenaries committing atrocities in Africa and attempting to camouflage it as a French operation, paying random dudes to commit easy but high social impact crimes like tagging a Holocauste monument, networks of propaganda accounts on social media to create or amplify anything that will raise anger etc.

Unrest anywhere in "the west" helps Russia. Russia would be delighted to see civil war in North America. They want us busy dealing with our own problems so we leave them alone and don't pay any attention to whatever other horrors they wish to achieve within their supposed "sphere of influence".

The USA and Canada, together, are the heart of a massive power block. Riving the two is a huge policy win for Russia.