There's a fair bit to sort out here. I actually think the question adumbrated in the question title is not precisely the one you want answered. As I see it, we don't have to wring our hands over whether we're being sufficiently open or fair to questions that have a numerological character. Try entering 'numerology' into the MO search bar, and you'll see quite a few good questions pop up. As I see it, it's not that there is some innate prejudice in the Community against 'numerology' as mathematicians use the word (there probably is prejudice toward its more mystical contexts). Of course not. We all have struggles not tied to deductive reasoning per se, where we look for patterns, apply guesswork, etc. etc., and occasionally ask each other for help. 

Speaking for myself, questions are approached on a case-by-case basis. Here are some of the criteria I apply. Is the question clear and precise? Does it seem likely that someone can answer it? Does the level seem appropriate for a professionalized community? Etc. And I think I'm not alone in taking that case-by-case approach. 

I have seen some good faith effort from you to try to understand the norms of the community and make adjustments to your questions. There seems to be some disagreement with my casting a fifth vote to reopen the thread 
https://mathoverflow.net/questions/288114/e-6-e-8-and-coxeters-anti-prismatic-projections-of-the-n-dimensional-cr where I had cast a fifth and final vote to reopen, based partly on my perception of good faith effort. And I must admit, I'm having some second thoughts. As mathematics goes, the question still seems pretty vague to me, which is to say I don't have a clear idea what's in your mind when you ask such questions, or how someone would know what you're after. That may be partly due to my shortcomings, but here again I don't think I'm alone in this, and I suspect you generally needs to work yet harder to bring some of these questions into a good useful shape for MO. The closures may be due to people who share these concerns. 

[I do often worry about knee-jerk reactions from the community. Hey, I worry about them in myself. So I struggle daily to maintain an open mind, and to seek pragmatic constructive solutions to problems as they arise. But, I'm struggling alongside other people here. May I say that I bristle a little at being painted as some sort of hero of free thought at MO -- maybe not as much as I bristle when I am portrayed as an *enemy* of free expression (as has sometimes happened), but still. It's just a little too inviting of invidious comparisons with others who I think are also acting in good faith. Cf. some of the discussions over at Math.SE meta, where I think my actions and attitudes have been overstated by you.] 

In addition to the suggestion that you endeavor to make your mathematical questions much clearer, I have some others that I hope you will take to heart, and which I think might help moving forward: 

* Resist the urge to leave so many comments. Very often when someone leaves a comment, you leave four or five in return. In ordinary conversation this would likely be experienced as being talked at. Actually, leaving excessive comments is considered a site violation. The lack of follow-up from your presumed interlocutor should be a sign not to go on and on. Part of the StackExchange model and software is that it is expressly *not* designed for extended discussion. 

* Resist the urge to philosophize. There has been way too much about Peircean abduction, or alleging an auto-immunity disorder within the community, to mention two specific things. As Lucia said succinctly: just stick to the math. I do think he (yes, he) is right that you've had a tendency to diagnose what is wrong in our community and what should be changed, and inevitably this provokes resentment, as you are still new here. 

* Adding to the last bullet point: please avoid any urge to get defensive about how your MO questions are treated within the MO questions themselves. This includes invoking names like that of Coxeter to defend your question as being research level. Really, the mathematics should speak for itself, and that should be the main, perhaps even the sole focus moving forward. 

Those are just a few general pointers; there may be more specific ones for individual questions. 

As for the case study: as I advised in response to an earlier meta question, in general a better approach for meta might be to ask whether the specific "numerological, abductive" question would be good for MO Main. Not whether we need to be more open to numerology, as I said before.