One could make the argument that someone unfamiliar with LaTeX probably won't have the requisite background to contribute meaningfully in this site. Granted, there are some peculiarities with MathJax.
But aside from that aside, here are a couple of points.
The
/help/formatting
is fairly standard across the network (I have only seen a different version on Stack Overflow and Server Fault, though I haven't checked all sites), and can only be edited by SE employees.A few sites have an additional
/help/notation
page in their Help Center (examples are physics.se, math.se, and chemistry.se) which gives some barebones introduction to the MathJax syntax, as well as links to more information. These additional Help Center pages are editable by site moderators, though they have to be inserted into the Help Center page by an employee.Of some note is the fact that on math.se the "How can I format mathematics here?" link is pinned to the top of the "Our Model" section of the Help Center. This gives it somewhat more visibility than the
/help/notation
pages of other sites. This is something that had to be done by an SE employee, but was pretty painless.
Instead of requesting a customized /help/formatting
page, it might be easier to request a /help/notation
page to be added, which can then be customized by the moderators, with the input of the broader community.
Note, too, that the side bar of the ask question page has a link for "MathJax help", albeit the target of the link isn't the greatest, IMHO. Math.se has had the target of this link changed to their own MathJax basic tutorial and quick reference meta thread. Something similar could be done here.