Nobody tried to install nuclear missiles in Ukraine and there are plenty of European countries that haven't joined NATO despite much closer ties to the west than Ukraine like Sweden and Finland. I think Ukrainians wouldn't even have considered that their ethnic brothers would attack them (and most ordinary Russians are probably still in denial about it) before Donbas in 2014 and last week which makes their joining NATO an absurdity, you don't need protection when you don't fear someone. Your neighbours joining NATO can be perfectly avoided if you stop invading them.