I get it. This is aimed at left-wing people who think their side can do no evil and thus proceed to censor any disagreement. But it's still funny to me that this whole thing needs to be preceded with 'the right is bad, but believe it or not, people on the left might do some bad things too', as if any side has a monopoly on virtue and goodness.
Imagine if, every time someone wanted to talk about helping end the obesity epidemic, many other people chimed in about how dare you talk about obesity when cancer still exists. And the only way you could make a point about obesity is to put a disclaimer that cancer is totally worse than obesity.