The wikipedia is a pretty good write up. but generally you see it in European or multicultural spaces more than American centered, though it has entered the discussions, most no one knows what it means when they are using it.
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I've found most use it to just refer to any communists at this point
People who use it that way are dipsticks, but I'm not surprised.
Dubcek was a communist, and so were most of those oppressed by the Soviet forces from which Tankies get their name.
There is a wild world of difference between the person who's like "Karl Marx was correct, but the USSR did a lot of extremely horrible things," and the kind of creep who openly stans Xi Jinping and Stalin.
Authoritarian communists. So, yes, they are pro-military
No, it's basically a dig at authoritarian communists. if you didnt know that you really dont need to worry about it, it's pretty much irrelevant unless you're chronically online
The TL;DR is someone who supports authoritarian regimes that 'are trying to achieve communism' to the degree that they support, often uncritically, the oppression caused by (self-claimed) communist regimes. Some examples of such regimes would be : the USSR, the Chinese Communist Party, North Korea and Russia.
They will often deny or severely undermine events such as the Holodomor, Uyghur genocide or the Tiananmen Square massacre.