That doesn’t fit the narrative, you’ve got to vilify the opposition. It feeds red meat to the left leaning sheeple. You’ve got to destroy Trump and everything associated or it might re-emerge. Grandma with her cane, waving a trump flag: insurrectionist or ill advised tourist? Yeah, there were a couple of bad actors but the vast, vast majority were just following the crowd inside, taking pictures etc. But that makes bad headlines.
Let’s put it in a context you can understand, Liberalism tells us it’s all about ones identity, gender, race, etc. They identified as Antifa and BLM hence it’s ok.