When liberals ask “Well why don’t you debate white nationalists/the alt-right/neo-Nazis and prove to them their ideas aren’t true and show them the logical reasons why?” The reason is threefold:
1.) We already tried that they don’t listen
2.) They’ve proven time and time again that their propaganda and talking points aren’t about what’s necessarily true but purveying a message.
3.) They aren’t debating in good faith and have no care for the general rules of discourse.
If you literally can’t win a debate with a Nazi, or can’t even manage to look better to observers, then I’d say you have serious problems that need to be addressed first.