I can't find a single reason why Russia should defend Armenia. And most importantly from whom? From Azerbaijan? Then why hasn't Arminia recognized the independence of Nagorno-Karabakh yet?
Armenians just want someone to do their dirty work for them.
"6D chess master" sliding slowly under the table
Politico:
We can’t rely on Russia to protect us anymore, “As a result of the events in Ukraine, the capabilities of Russia have changed,” Armenian PM says
Once one of the Kremlin’s closest allies, Armenia is now conducting joint drills with US soldiers.
https://www.politico.eu/article/we-cant-rely-russia-protect-us-anymore-nikol-pashinyan-armenia-pm/