We hit the nesting limit elsewhere:

I'm saying the exact same thing right back at you: Flagging, just like upvoting, is me using my Steem Power as I see fit. What gives you the right to stop me?

Your market metaphor is not apt. The Steem marketplace has a fixed maximum daily sales amount that is rewarded based on the relative Steem Power being flexed behind each piece of content. No flea market or farmer's market works like that. Hence, your comparison is just not apt. It doesn't work.

How do you know it doesn't work? As far as I know it hasn't been tried. In addition, up vote only does not stop you from NOT supporting something. You simply don't vote. It does prevent you from deciding that you don't like me, or value something so you can now strip the value other people perceived it had.

However, let's go to this idea that due to a fixed amount when we remove that value it is returned to the pool and redistributed. As far as I can tell it is not redistributed based upon votes, but instead would be dumped into the pool that is distributed to people across the board via steem power. So we could simply remove voting at all and everyone would get paid based upon their steem power. I don't see that as offering much incentive so I don't endorse that and I am certain you wouldn't either. Yet that is me taking it to an extreme of everyone cancelling out each others vote.

Please consider this hypothetical scenario.

Someone (neither you or I) writes a rather brilliant article on some philosophical study and they put a lot of work into it. Some people value that effort and vote it up to $10.00. You come along and have accumulated power and the study contradicts your personal belief so you vote it down to $0.00.

Now the people that value it have had you cancel out their investment in steem. You also will have crushed that other person's work due to you seeing it as having no value due to a dogmatic or personal preference.

I recall the instance with @dollarvigilante and you likely do as well where his post about tips for people using steem was voted down to about 10%. While I personally think that celebrities are a bit overpaid for some of their posts, other people do not agree with me. In that particular case the reason it was down voted to 10% it's original value was because there were too many similar articles already posted before.

Due to discoverability dollarvigilante was new here, and it is not like it is easy to find such posts. So that post obviously had value to some people. I do think a large amount of the value of the post was actually due to the celebrity nature of the dollarvigilante, yet that was not the reason given.

Should people need to justify their actions? Currently if it stays as it is no. You should be able to go down vote nuts if you want to. Yet there will be consequences and it will cause war. It is pretty much guaranteed to happen and there is plenty of precedence to back that up.

So I am NOT 100% certain up votes only would fix the problem. It hasn't been tried. Yet I am rather fond of experiments. I am also not one of those that if it is tried I'll doggedly demand we keep doing it. This is not about me being right or wrong. It is simply perceiving what is interpreted as hostile actions by many people (read the posts, and the topic comes up a lot) and I actually do tend to adhere to the NAP as much as possible. I also have a strong sense of justice so if I perceive people being attacked I like to be the hero sometimes stupidly so. So from an EGO perspective... that actually is an ego problem I have. ;)