I don't know about Mexico or Canada, but Estonia, Latvia, Lithuania and Poland are all both Russia's neighbours and NATO members.

Either Russia is not a superpower or it's not that relevant.

Or Russia does not find those countries to be enough of a threat either due to size, military force, existing relationships, geographical boundaries, or a multitude of other factors. Or maybe Russia has begrudgingly accepted those countries joining NATO, but the last straw was a huge neighbor like Ukraine joining that is strategically important to them.