Funny that I read about the topic here as I just today commented someone who said that he doesn't downvote without giving a reason and that this should be common courtesy.

This is a nice paradox: having the courtesy to explain to someone why they have been flagged. To use an analogy in the physical encounter, it would be like punching someone unexpectedly in the stomach. Then you would bow politely and say gently, "I punched you in the stomach because I don't support your action."

The other person who has just been punched answers without resentment: "Thank you. I needed that."

In so far as both acknowledge the premise that one should express one's disagreement to someone with a measure which, precisely because it is considered painful, should have its effectiveness, everything is fine, isn't it?

An even more beautiful paradox would be to ask in advance whether the person I am about to downvote has the same premise? If he answers "yes", then my intention to flag him would meet with no resistance. The complete agreement to be flagged would make itself superfluous in this way, wouldn't it?

.....

To answer your question, I place it here so I can better respond to it:

Do you think that people who disagree should (EITHER) express their disagreement with reasonable words (OR) simply avoid each other (use the "mute" function)?

I speak from my experience only. About myself and those with whom disagreement arose. I noticed when my inner disagreement with how a topic was published and represented by that human was already taking up the biggest space, no debate and direct argument seemed to reach my disputant. I was particularly shocked by him because in all the weeks before we had some quite good conversations and I could not understand this part of his notion. We argued and I eventually pressed the "mute" button. Not to prevent me from being approached by him but prevent myself to come up with further arguments as well as despair.

More than a year later I see it more relaxed. Even though I might think not having transferred a message which meant a lot to me, I have hope that it was delivered, because of our good contact beforehand. That's all what one can do in case of disagreement. I eventually un-muted him and left a comment here and there. For the time being, I found it was needed. One needs protection from oneself once in a while.

I have a no flag policy. Only up- never downvote anyone. The one and only group I know which also has this policy is @steemstem and I find, they drive well with it. I haven't checked recently but I guess it's still the same.

What would interest me right now is to see a statistic which shows the tendency of using downvotes from the last 8 months or so. People argue a lot on the surface. It often contradicts what the actually do.

Censoring is not supported by me.