You've exaggerated in a few places, as follows.

if one person dislikes a comment, it shouldn't be responded to?

It's mild evidence for the statement that it shouldn't be responded to.

This makes the site enforce a tyranny of the majority.

It's not clear that there is a "tyranny" with typical connotations, so the word shouldn't be used without clarification.

I don't think Alice should be prohibited from responding to Bob, ever. If two users create drama with back-and-forth responses, they have both chosen to do so.

Not "ever". The choices that affect many other people negatively should be discouraged, or their effect neutralized in some way, if possible.