In my country we still have a old school communist party, and despite their radical ideas like saying north Korea is a democracy or support maduro in Venezuela, when you hear their political campaign is all about raising minimum wage and a restricted House market. In the other way, when we look at the far right party, it's all about how the immigrants are eating tax money or defending a small government with a total control for one leader.
So it's not that radical left doesn't exist, it's just that they drop their guns and what's left it's not that loud.
3) the radical left is a bogeyman and the reason you don't see many of them is that they're exceptionally rare.
4) radical leftists have better opsec after generations of actual persecution and censorship, and don't do youtube
5) I think tiktok is more popular with the left?