In modern parlance 'Tankie' is generally used to refer to people on the left who support authoritarian governments. (see second paragraph in definition section:

In modern parlance 'Tankie' is generally used to refer to people on the left who support authoritarian governments. (see second paragraph in definition section: https://en.wikipedia.org/wiki/Tankie#Definition https://en.wikipedia.org/wiki/Tankie#Definition) So yeah basically the intersection of "left wing" and "thinks the Chinese government is great" (which as you point out is not a particularly large group of people, at least in the USA).