This is a mess of our own (well NATO's) making. Russia has been raising concerns about NATO expansion for decades. We were given a warning this would happen in 2014 when pro-western groups overthrew the democratically elected pro-russian government and Russia immediately moved to annex the Crimea and protect their black sea fleet. No one in the West seemed to care much about democracy then as it suited us to have leaders aligned with the West in power, but we knew from then on in there was no way Russia would allow NATO on their doorstep.
And you can argue that a country should be allowed to join up to an organisation if they want to, but that's not reality. Imagine the roles were reversed and Russia created an organisation specifically designed for containing USA and UK aggression. What do you think would happen if the likes of Iran, Saudi Arabia, or Turkey tried to join that, let alone a France or Mexico? We'd be raining hellfire on them before the ink was dry. Leaders from NATO and had the chance to avoid this outcome but didn't want too and now as per usual innocent people will pay with their lives.