I think we're talking about slightly different topics here. What I'm hearing from you is along the lines of "I shouldn't feel obligated to spend my time listeni

I think we're talking about slightly different topics here. What I'm hearing from you is along the lines of "I shouldn't feel obligated to spend my time listening to racists about their racist ideology." I was trying to aim more at "we shouldn't interfere with a racist having on-topic technology discussions with third parties." Both the differences are important. Choosing who you will and won't engage with is a different beast than who is and isn't allowed to talk about things. Whether certain topics are appropriate for a given context is a different thing than whether choosing wrong on one topic means you are no longer an appropriate person to talk about another. In short, I'm encouraging you to ignore the crank, but not censor him from talking about context-relevant topics.