Honestly, I don't get what the exact question is, and the more I look at it the more it resembles a rant.
There are at least three loosely bound topics raised, which were discussed on Meta numerous times.
I'm going to leave a few URLs and share some personal experience:
1. Silent downvoting
This is entirely up to downvoter whether to leave a comment or take French leave: that's how all SE sites operate by design, whether you like it or not.
I rarely downvote, and if I do, I tend to leave a comment unless the answer is a blatant mess or spam.
To me it seems the best you can do is to leave a comment asking for the reason of downvoting and how you can improve the answer.
This way you show interest in improvement, and an adequate user (BTW, not necessarily the downvoter) would answer back pointing out what can be improved (if they see it, of course). Further reading:
2. Erroneous formatting by new users
I agree that we are all humans and humans are prone to doing mistakes, and it's fine.
However, you are required to demonstrate at least minimal skill in writing by following English grammar, punctuation, capitalization and other rules alongside with proper modest formatting.
If you fail to comply with the basics, this shows that you don't care whether other users will be able to conveniently read and understand the post you've written.
In such a case, why would you care about the downvotes and reasons for them at all?
The antidote is composed of these actions:
- Lurk a lot at the beginning (search the Meta or see how similar Q&As are formatted — you can use tags for that).
- Observe and start with simple small answers or edits.
Take an example from more experienced users, read the comments on editing and don't hesitate to ask if you spent hours searching, let's say, how to change alignment in a table within a column or something similar.
- Practice.
You can instantly see the preview of your final post plus there is a sandbox for sharpening your skills.
Seriously, MathJax and Markdown are probably not the easiest things in the world, but they are certainly manageable.
Besides, if you are a STEM scientist, you already know the basics since MathJax borrowed a lot from $\mathrm{\LaTeX}$ which is used for serious scientific publishing and Markdown is just extremely abundant — if you are using version control systems with GitHub or GitLab, you already know Markdown.
There are several dozens of relevant topics, maybe have a look at these:
3. Lack of illustrations
I'm not sure why this is a problem.
To me it's easier to bust-open Inkscape and draw something crude, scan a book or crop a PDF page than to write an essay and tediously answer numerous clarifying questions afterwards.
"Show, don't tell", as they say; also, don't hesitate to learn the good new tools for producing graphics, it's a good investment.
As for the focus on concepts rather than on formatting part, I vastly disagree.
This is known as a Form-and-Content concept, and it's been proven by many philosophers that separation of those lead to deterioration.
I prefer to see formatting as a part of language, even though it's not a linguistic construct per se.
I've used this analogy numerous times, but again, using the same language (English + math + standardized formatting) helps scientists to build the tower of Babel further without worrying about the god's will to divide.
All in all, proper and standardized tooling makes life easier: the creator doesn't waste time thinking what's the right way of putting the content together, and the reader can quicker consume and understand the delivered content since it's clear and unambiguous.