I believe in socialism, but I feel Stalin shouldn't be idolised due to things like the Gulag.
I would like more people to become socialist, but I feel not condemning Stalin doesn't help the cause.
I've tried to have a constructieve conversation about this, but I basically get angry comments calling me stupid for believing he did atrocious things.
That's not how you win someone over.
I struggle to believe the Gulag etc. Never happened, and if it happened I firmly believe Stalin should be condemned.
That sounds to me like you were just dealing with bad faith actors, which isn't uncommon here unfortunately.
I think we both agree on what it's intended use is meant to be for. I guess you've just had the misfortune of dealing with people misusing the label to shut down any actual discussion.
What I am describing is by far the most common usage of the term I have seen, to the point that it might as well be the only usage. The intended usage of "tankie" has become weaponized discussion-avoidance and serves as a cheap copout to prevent tackling uncomfortable topics.