They basically view the "western" capitalist system as the source of a lot of pain and misery and so "evil". America is viewed as the leader of this system.

Thus a country which pushes back on this system must be good. Brazil, China, Cuba, Iran, North Korea, Russia, etc.. are examples of countries pushing back on this system or America.

Under this logic the USSR was one of the good guys and so its actions were righteous.

This is how tankies got their name, they supported the USSR invasion of Hungry when the wrong type of communist won power.

Even though Russia is more extreme in its capitalist position, the Russia demand for a multi polar world order and attempts to compete with the USA, make them heroes to many Tankies. They will justify this as Russia is the successor to the USSR.

So you will see Tankies support the Russian invasion of Ukraine. They will often claim Ukraine provoked Russia, that both sides are at fault, Russias fears about NATO justifiy the invasion, etc..

The problem with this world view is reality, Russia has been raping women and children, castrating PoW's, kidnapping children, operating mass torture centre's, etc..

When faced with Russian actions it's impossible to justify them. So a tankie simply declares all of that as "propaganda" and then looks for sources of information that help justify their position (ironically Russian state produced propaganda).