Many things to respond... let's see if I can reply to everything using one paragraph;

The way I measure whether I'm doing a good job decreasing VP abuse on Steem, is by how much SP that is held by abusers is powered down.
A 50K limit is fairly arbitrary. Just to avoid a situation that I'm at war with 6 Orcas, which can together bundle up and mitigate everything I do. Whether I'm flagging 10 people with 10K SP each, or 50 with a combined SP of 75K isn't the point. How many of them cease operations is the only metric that matters.(again, how much SP is powered down and sold, regardless of how many people actually held it).
If I'm being diligent about who (or more accurately which posts) I flag, it doesn't matter whether the flagee refuses to understand that it isn't personal. I can explain why the flag was placed on his post. But if his too stubborn, I'm not going to be his therapist.

Regarding engagement, both are (almost) equally important. You can't have a good social network without a large user base. But you also can't have a large user base if not enough rewards are available for great content creators (we're not really built for FB like activity, but let's just agree to disagree how much Steem is like FB and how much like medium). And why do I think that abusers affect the available rewards that much? Well, because they are. Take a look at this chart from from July 2018, to April 2019, SFR had responded to over 13,500(!!!) instances of abuse. And that's only for those they CAUGHT, 13,500+ upvotes that took rewards from content creators that actually care about the future of our platform, and instead rewarded users that see Steem as nothing more as a cash cow.

This ecosystem needs both curators (those who focus on upvoting quality posts), and abuse fighters (those who try to make the curators VP worth more), those are two sides of the same hammer. You need both for the platform to thrive.

And don't get me started on the risk of the abusers being able to overpower everyone else... we'll be slaves if that happens. And STEEM will rapidly move towards 0.00000001BTC

So basically, curators distribute the rewards, but abuse fighters make sure they actually have enough rewards to distribute

#CleanSTEEM