Yeah, I'm sure USA would go to war with Mexico, deny it and annex a part of it. Russia has military bases near NATO countries as well. I'm not rationalising USA army interventions but comparing it to Russia in this case is ridiculous.
Tell that to Kuba when Russia tried to install army equipment there.
And USA has about 800 military bases in the whole world outside of USA. Russia has 8 or 9 outside of Russia. USA is spending hundreds of billions of dollars annually just to support those military bases. I know I would be pissed about that if I were a US citizen.