Leftists have a separate set of rules for themselves and conservatives.
It’s not a liberal vs. conservative thing. It’s a black vs. white thing. As Thomas Lifson wrote today, “The mostly unspoken rules of contemporary American society hold that African Americans cannot be insulted in ways that Caucasians and some other minorities can be. This is mostly a legacy of slavery and the official discrimination that followed under Jim Crow laws passed by Democrat-controlled governmental units in the post-Civil War South.”