Saying politics should be kept out of metal showcases a fundamental misunderstanding of the genre, plain and simple. Metal has always been political – from Black Sabbath's "War Pigs" to Metallica's "One"; from basically everything Megadeth has ever done to loads of controversial black metal over the years, for better or worse. The genre is inherently political, as is almost all other forms of art.
Within Temptation's Sharon den Adel and Robert Westerholt recently spoke to Metal Hammer about exactly that topic, saying their music has certainly drawn ire for being "too political."
"I deleted a message on Facebook," said den Adel regarding Within Temptation's pro-Ukraine single "Raise Your Banner" in 2019. "He said, 'You're preaching about freedom and then you preach war. You slut.' It means you would give your life to have freedom. So, if he had put five minutes of effort into reading the lyrics, then he would know 'Raise Your Banner' is taking a stand."
"What annoys me a lot is that people say, 'Don't talk about politics,'" added Westerholt. "It's not even politics. It's your opinion as an artist. Artists have opinions. That's what art is for. That's what makes it interesting."
And sure, nobody's saying to get out there push your politics into everyone's face every chance you get. It's just that art is generally political and, like it or not, bands like Within Temptation (and Megadeth, and Aaron Lewis, and Panoption, etc.) are always going to have that sort of messaging in their music. There's always the option of simply not listening, y'know?