Imperial powers don't give countries around them independence. They try to control more and more. And Russia was fine with all of eastern europe being independent on one condition. That NATO shouldn't move even an inch to the east. And you can find US papers that talk about that, you can find Gorbachev saying that. It's something out there not difficult to find. Well, it's not really because there never was an on paper agreement. There were just talks that came to an agreement and the fact it never was put on paper, even though both sides mention it, was used as an excuse to move NATO east.
I hope you realize how dumb and schizophrenic this sounds. Let me rephase your sentence
"This isn't about Ukraine having US troops next to Russia border, because it will have US troops next to it's border"
If this is the logic we have on the west, no one should be surprised we have this war. Any country who will recieve a message it will have guns pointed at it from every direction no matter what will be forced to military action to prevent that.
And you know what's funny? I made the arguments above to many people by now. Online and irl. And it both cases minority seems to reply reasonable to it. I actually recieved pretty reasonable responses. Then there are people like you who short circut like some NPC and start spewing nonesense everywhere or repeat themselves 10 times with hopes that somehow doing that the 10th time will make them seem reasonable.