When I ask a question that is inconvenient for lefties, I like to try to predict which specific evasion technique they will likely use. I know they are going to dodge, divert, invert, ignore, redefine, or otherwise evade answering with an answer that demonstrates that they have read and understand the opening post, so I like to try and guess which one they will use.
There is no good reason why it is only offensive for whites to where blackface while blacks are free to wear whiteface, and there is no good reason why my spellchecker underlines whiteface in red but does not underline blackface. Lefties cannot provide a good reason for this, so they will evade answering.