Its nonsense. Russia isn't going to start a nuclear war over some pissant Ukrainian strike on Russian territory. Under Russian law, they promise no first use of nuclear weapons except in the event of an overwhelming attack which threatens the very existence of the state. The Ukrainian military right now couldn't threaten the existence of a jelly donut without NATO's help, and even with NATO's help, short supply lines, and a numerical advantage, they're being mauled.

Russia has not yet deployed the extra 300,000 men they called up a few months ago. A private mercenary company, Wagner, just slaughtered the Ukrainians with all their NATO equipment and took Soledar, and now they're well on their way to taking Bakhmut. Once that happens, chances are good that the Russians will finish the liberation of Donbass.

The only thing that u/EndJewWhiteSupremacy said that was even close to reality is that NATO could push all the way to Moscow through Ukraine, or at least they could if Russia was fast asleep and helpless. That is the point of the war: Ukraine is critical to Russia's security. Russia has been invaded five times in the last few hundred years, and each time the invasion forces went through Ukraine: Sweden, France, Poland and Germany twice.

Which is why they are willing to fight to keep Ukraine neutral and out of NATO.