It's a real shame tattoo ink isn't regulated in the US, at all.
Then you choose which to buy.
And then Amazon sends your artist the comingled counterfeit ink from Storage Tote #29924
As a platform, they can probably get around counterfeit items being listed/sold, but sending one from a different seller seems it might open them up to legal risk if Amazon knows there's counterfeits floating around.
I'm sure we all accept the risk in the fine print somewhere, but that only matters until it makes the news and a politician thinks they can get reelected by going after them