I'll give you as honest an answer as I can, with some context. My reasons for staying have evolved over time. Recent events have sorta been a reality check for me, making me give SE some hard thought I would otherwise not have done.
Until maybe a year ago, I thought SE was the best thing since sliced bread. I became addicted to the place and really enjoyed being here. I became perhaps too invested, both emotionally and in terms of time and effort spent here.
Then SE's focus moved away from content quality. I stuck around because it is satisfying to help people solve problems, and I still felt it important to help curate the sites I spent time on. My participation became more "in spite of" SE corporate than because of it. Over the years, I had invested a ridiculous amount of time and effort, and still felt tied to the sites, but the environment was starting to burn me out.
The recent events disgusted me and were kind of a last straw. I was about to walk away from SE when David Fullerton posted his apology.
It made me take a step back and reflect. If I was so disgusted with SE, why did I spend a week, or whatever the period was, glued to MSE and venting in posts and comments? Why did I care?
I came across a post where somebody observed that anger meant that the person still cared, whereas apathy meant the person no longer did. I thought I had been getting apathetic over the last year, but I realized that I still care about the sites, themselves.
I decided to delay any action to see how things fall out. "Why" I stay is no longer a simple question. The "why" part of it will balance positives and negatives (and won't be easy). For me, if I stay it will be more a question of "how"; the nature of my participation.
I suspect it will be a long time before I feel invested in the place again and would consider volunteering for a moderator position. If SE totally makes things right with Monica, comes up with a reasonable CoC, and starts focusing again on quality, I will stay for the same reason I originally joined -- it's the best platform for building knowledge and helping people solve problems. If I want to continue these activities, it would be hard to find a better venue to do it. I will continue to help curate the sites I use. And because it's addicting.
Short of those changes by SE, I would have to do more soul searching. I would likely participate for less altruistic reasons; at a minimum, I could see using SE for my own questions, maybe answering an occasional interesting question to help someone else. Who knows how that might change over time. If SE continues to treat experienced users as commodities, or continues policies that make quality less important, I probably wouldn't continue to volunteer my time curating sites. But if the terms of the new CoC aren't something I can endorse, remaining will be untenable, regardless of the reasons I might prefer to stay.