People aren't changing or modifying their tunes because they've been too loud already in shouting down opposition to it. I think pride and ego are largely to blame.
That's one possible explanation. Another is that people who disagree with you aren't changing their minds because your arguments haven't convinced them, and that your own pride and ego make you characterize - or rather caricature - the expression of a view you disagree with as an egotistical "shouting down" of "opposition". I lean toward the second explanation myself.