Yes, it is an obscure historical term that fell out of use for decades and has no relevance today. No communists use the word ‘tankie’, including communists who do not support the Soviet Union (eg Trotskyists) or modern China (eg certain Maoists). It is a term used by anti-communists, and “communists” whose understanding derives from Wikipedia rather than Marxist theory.
That is in part what makes it so malign. It is a term of propaganda and obfuscation. People who would fall under the term of ‘tankie’ include: Malcom X, all members of the Black Panther Party, Che Guevara, Albert Einstein, Bertrand Russel, Jean Paul Sartre, Nina Simone, etc. In other words, all communists. 196 should be open about their political position instead of hiding behind vagaries and disinformation.
The concept of class warfare is fundamental to Marxist theory. To quote the man himself, ‘When our turn comes, we shall not make excuses for the terror’. We are not Utopianists, and we accept that the Bourgeoisie must be destroyed in order to free humanity from exploitation.

“Liberal” is the name that supporters of liberal capitalism use to refer to themselves. It has a precise and accepted meaning.
“Tankie” has no defined meaning, which is why it is not used by communists. In its vagueness it is used to associate Marxists with crypto-fascists and non-Marxist ideas, and to obfuscate the meaning of Marxism. And in so far as it associates the kind of people who died to liberate Auschwitz with the kind of people who built that place, it is offensive.
If there is no malign intent behind the term ‘tankie’, then why does anyone use that term instead of communist? Why doesn’t 196 have “fuck communists” in their banner instead of “fuck tankies”?

I came from wealth. It certainly didn’t make me a communist. What did that, was the years I spent working in healthcare in various developing countries, and watching people die because they couldn’t afford proper treatment. Although I suppose thinking about where I came from also helped.