Tankie always meant a fan of authoritarianism but not of the nazi variety. And hand to hand with that goes hate for America, but hate for America isn't enough on it's own, it should be paired with love of Strong Hand Of The East.
Tankie thinks China, Russia, North Korea are just swell, and not because of some underlying ideology, but because they have an authoritarian model of governance and generally in opposition to the west to some degree.
And that's the reason why it's so hard to define for some people, boiled down to it's definition, it's very hard to spin into something universally good, so talking to a general public they have to do what authoritarian lovers from the other side of the spectrum call "hiding the power lever", which muddies the water.