It depends on the fans.
Are they overall metal fans, or are they fans that listen to the artist for the lyrics themselves?
I know plenty of fans of groups like System of a Down, The Clash, even Green Day who legitimately give no credence to the anti-capitalist, anti-racist, and socialist lyrics of the group; they just enjoy the grooves and hooks of the songs.
I also know a lot of people who listen to those artists BECAUSE OF the concepts and the message itself.
Remember Chocolate Rain?
Song was exclusively about systemic racism, and Blackness in the US. Every single line of the song.
It went STRAIGHT over the vast majority of White people's heads.
Including the executives of Coca-Cola
So I automatically assume that whoever is listening, especially if they're White, has no idea what's going on until proven otherwise