>Excuse me?
Let's connect the dots, shall we?
Your original hysterical post was that somehow countries freely joining NATO infringes on Russia's security somehow.
However, if we look at the example of Iraq war:
1) Iraq only borders one NATO country (Turkey), and Turkey was not involved in the war – the invasion was launched from a non-NATO country (Kuwait).
1a) USA is half the world away from Iraq, just as it's half the world away from Russia. This changes nothing.
1b) Likewise, Ukraine being or not being a NATO member doesn't change anything about possibility of USA using its territory to launch an invasion on Russia.
2) You claim that NATO cannot be considered "merely a defensive alliance" because NATO countries... are also allowed to freely join aggressive operations by USA? Even though majority of NATO countries would not cooperate (and in fact Germany raised a stink in the UN over the Iraq war)?
2a) Conversely, in the case USA would decide to invade Russia from Ukraine, nothing about NATO forces European countries to cooperate. (Germany surely wouldn't, for that matter.)
2b) What's more, the American nuclear weapons stationed in Europe are, as per the nuclear sharing agreement, under a dual key system, meaning that both USA and the country they're stationed in need to agree for them to be used. So the "b-but USA is allowed to move in da big nword rokits!!!!" argument is also meaningless.
So, to do a synthesis:
3a) USA can invade from NATO or non-NATO countries, this is not a problem, and allegedly NATO missions (such as Iraq war) were based from non-NATO countries while majority of NATO countries didn't participate.
3b) Likewise, since NATO members are completely free in whether they want to back American offensives or not (which would of course be within framework of NATO due to logistics), if European countries would join such an invasion, they just as likely would join if not a formal NATO member (like non-NATO member allies did in Iraq).
Which leads to the conclusion:
4) Whether Ukraine is or isn't a NATO member is meaningless for Russia's geopolitical security. What you should worry about instead is make sure that non-NATO members next to you don't want to seek protection from USA, and that NATO members next to you would not support an invasion should USA decide to do it.