This doesn't just happen with Third Reich memorabilia either. There are plenty of collectors who have USSR era memorabilia as well. The hammer & sickle is just as detestable as the swastika.
Panzer, it just not quite the same to a large majority of the public. Regardless of what the hammer and sickle represented, it's symbolism is not nearly as restricted as Nazi symbols. I used to collect WW I and WW II German stuff, but quit because there were too many fakes flooding the market. Obviously, primo German stuff is also much rarer since the Nazi regime ended many decades before the Soviet Union.
EBay will not let one list anything that shows either the swastika or SS symbols while they could care less about
former USSR stuff. They also forbid items associated with the KKK. However, nothing about the symbolism of the former Soviet Union. In fact hammer & sickle stuff is considered sort of campy.
I've been slowly selling off some of my militaria since I have no family to leave it to. I recently had a listing for a mint WW II German DAK (Africa corps)tropical pith helmet removed because of EBay offensive symbolism policies. I had covered up the Wehrmacht eagle/Swastika badge on the left side, but that wasn't good enough. It has to be removed and one has to pretend that it doesn't exist.
It wasn't caught right away, so I already had bidders on it and it was already up to $350 with a week to go when they pulled it. It would have easily topped $500--maybe even $600 since it was close to mint.
I sold a WW I enlisted cap a week earlier, but because it was Imperial Germany there was no issue. The same goes for former Soviet Union stuff too regardless of the period. Stalin's misdeeds against humanity just never got near the bad press that Hitler and his gang got.
One just has to play the game to get past EBay's uninformed, but politically correct police.
Cheers