That's because of corruption. As of now communism to be implemented requires authoritarianism. Authoritarianism is the main reason why communism is bad.
Currently both, tankies as well as far right don't really care about socialism (if tankies cared about socialism they wouldn't support China or Russia). All they are supporting is authoritarianism.
What far right labels as far left (in US at least) are people who support liberal democracy with protections and safety nets for working class. The "most radical" Bernie Sanders is exactly for that.
There might be actual communist parties in Europe, they hardly have any support.
Ok, then it looks like we are on the same page on that.
Though, seeing tankies support Russia and China tells me they don't care about social aspects of communism, so the only thing left is authoritarianism.
The term might be even more appropriate now as it originates, because they basically supported using tanks against the population to squash Hungarian Uprising. A totally authoritarian move.
At that point there's not much difference between them and today's far right. I mean tankies will openly say they support communism, but their actions shows that's not what they are truly after.
To me it looks like tankies were product of Soviet propaganda while MAGA is a product of Russian propaganda, and that's why they both share so many common views.