There’s a massive strain of conservatism that runs through hardcore (particularly US hardcore) despite how enlightened a lot of hardcore fans like to assert their scene is - definitely not just Slayer / metal fans.
That said, think we can all agree that that song was a very bad idea to begin with and covering it even more so. Slayer have made a fair few fairly terrible decisions throughout their career, it’s fair to say. Personally I don’t think that this is the be all and end all, but can understand if people do