In regards to opposing ‘cancel culture’, I agree with your overall view but I have a comment on the logic. Democracy is the rule of the majority. Democracy is really a means to an end. The objective is NOT democracy but rather self-determination. Sometimes, the needs of the few must be placed above the needs of the many. To take an extreme example, imagine a bigoted majority voting on whether a minority group should be exterminated! That would be democratic but fails the objective of self-determination. So self-determination is far more important than democracy but democracy is possibly one of the best currently known means to achieve self-determination.

The concept you used of the ‘sum total of this speech’ being increased is really a measure of the sum-total of self-determination in which the speech of those most affected should take precedence over the majority’s democratic right. So, yes ‘cancel culture’ may sometimes be undemocratic but it serves the objective that democracy tries to achieve which is self-determination.