From wikipedia
Tankie is a pejorative label for communists and those who align with Marxism–Leninism ideology. More generally, the term "tankie" has been applied for those who express support for one-party socialist republics that are associated with Marxism–Leninism, whether contemporary or historical.
They usually praise communism and ignore the flaws and horrible practices of things like the U.S.S.R
Why did you put the title in quotes