I think we'll just have to agree to disagree. First, a few points for clarity.
If I go to Settings -> Reading, select "A static page," and skip both page choices, the result isn't what you're saying: the selection automatically reverts to "Your latest posts" when I click "Save Changes" (in both browsers I use); if I select a posts page but skip selecting a front page, the selection sticks but the blog front displays the latest posts.
Yes, that only works on some themes. To reproduce it on all themes, set your front and posts page, then either delete those pages or set them as drafts (you'll need other published posts and pages to see the mess). I suppose that may not even work on all themes, but it works on more that just not choosing pages. The issue is related to how the theme is designed, and I haven't tested all 220 yet.
The OP's front didn't display "all pages and posts", it displayed two static pages only, plus a malformed comment section below the About page.
Yes, that's a variation of the problem, but still the same problem. The comments section was coming from the page. To clarify, the issue is with how a theme behaves when the setting is accidentally invalidated. It's not an ideal situation, probably not consistant, but not really a bug. We are looking into it, but it's not as high priority as most cases.
The About page did show up correctly as the blog front from the start, and the problem cropped up when the Funders page was turned into a child to the About page. The issue was "resolved" because the Funders page isn't a child page anymore - which is what I wanted to suggest anyway (that's why I asked the OP "why do you want the Funders page to be a child page?").
I have access to the blog's Dashboard, which I used to investigate the issue, so I am well aware of what resolved the situation. Maybe setting the page as a parent was part of the fix (it was set as parent when I got there, but I haven't been able to reproduce that part of the issue), but the blog was still largely a mess. Finalizing the front page settings is what solved that mess.
Overall, the issues was an accidentally invalidated front page setting, and that is on our watchlist.
I'm not saying that you didn't have a hand in resolving this, but from my perspective, finalizing the front page setting solved the messy front page, which is what I was focussing on.