What I have found personally is that one thing Steem is very good at is holding discussions (sometimes arguments) but without it spilling into flags.

I agree with this sentences. One that I notice lately is... some of the newbies maybe didn't know yet the meaning of spamming other content and yet once they start asking for upvote in one's comment box, their post are ignore eventhough they actually have a good writting of their own.
I took the initiative to reply their comment and gave a little bit of explanantion so that they won't fall into the 'flag zone'as I called it.
Sometimes, I think flagging without looking throughly become the cause of many abandoned account in this platform.

People are afraid to write eventhough steemit is actually a freewrite community that support good contents.(My opinion will be different for those who are taking this platform for granted)

In my opinion, argumentation is part of the road to building strong relationships through cooperation to solve problems facing both parties. This in turn is the way to also build strong communities as they are comfortable to tackle the challenges they face even if they happen to be in uncomfortable or taboo areas.

I can't agree more with this one.

So, the answer to a strong community isn't ending arguments, it is learning how to argue well enough that solutions are created instead of walls to defend what isn't working. Not an easy task but it is up to each individual to develop their skills to achieve this.

You have explain this part perfectly well.

Retaliatory flags are stupid and serve no real purpose...

My understanding in english is not so good and I don't quite understand the exact meaning of heavily staked...
but in my opinion, flag actually serve the purpose of protecting this community from those who do not appreciate other original content.

But me myself actually doesn't like the idea of flagging other content. I think it is better to leave them a comment of my thought and if they still didn't change then I will just ignore them and maybe someday they will have the initiative to write a better content.
I chose to ignore because by ignoring they will have to take a long way up and that could be the time needed for someone to truly u derstand this community litle by little.

Just a share of thought though
Hopefully none taken.