When someone disagrees with you, you have the opportunity to more clearly define what you think. This might mean changing your mind to a greater or lesser degree; it could mean understanding more completely why you hold the view you already have. If the votes show that a lot of people disagree with you, well, conventional wisdom is often enough not very wise.

In my experience, fediverse people have been more reasonable than reddit people - but you're going to find petulant children on any public forum.