It is because of the hypocrisy. When the incident involves 'right-wing' politics there is a call for condemnation. When there is a 'left-wing' or at least left sympathizing attack, the call is for unification.
Half of America is fuking sick and tired of the two-tiered system where one side gets understanding and sympathy while the other side side gets endless hyperbolic condemnation. I don't care what some dik from All-State says, but I do care that brain-dead idiot who has been in the white house for the last four years has endlessly gone on about how the boogeyman of white nationalism (MAGA in the minds of retards) is the biggest threat to this country. Let's condemn these acts of violence and stop belittling to us about how ISIS is no threat, but freedom-loving Americans are.
So yeah, fuk the idiots. We spent 4 years beating up MAGA over some phoney insurrection BS where the only people murdered were by the state vs. this attack which killed 15 innocent people. It makes no logical sense, except the left views MAGA as subhuman not worthy of being treated fairly and with respect.