The title says it all, is there a way to get in contact which users who consistently post answers without using $\LaTeX$? I've come across a user who does that and (as I had some free time) edited about 10-15 of his posts, some of his answers were barely readable; on each post I left a comment including a link to the MathJax tutorial. He still keeps posting answers without using $\LaTeX$, so is there anything else besides editing and commenting one can do?
It works like this. People can post solutions to problems all they want without MathJax/LaTeX, which is the lingua franca here. I do not have to bother reading their solution. If the OP believes it unfair that his/her solution does not get the requisite attention, then they can continue to post as they always have with the same results.
I had a situation today in which someone posted a poorly-formatted solution, which had fatal problems unrelated to the poor formatting. The poster was incredulous when I told him his derivation was too hard to follow for me to provide any useful feedback. Nothing I could do for that guy (who indeed deleted his answer eventually.)
I know of some experienced users on Math.SE who regularly post excellent answers, but due to physical disabilities or technological inexpertise have a lot of difficulty typing in $\LaTeX$.
I'm not saying all users have an actual problem, but for the sake of those who do, it's worth giving them the benefit of the doubt.
To @NajibIdrissi's comment - People who have sight problems may not use regular monitors or browsers, and can't always see the outputted $\LaTeX$, so I can understand that they’d rather not type it in the first place. As for technical expertise, Learning such skills above a certain age may not be trivial, and there's no reason why we'd want to lose a professional (though older) Mathematician just because it means some of us younger members will have to do some editing work.
A constructive suggestion to the Stack Exchange features:
a) Why not implement $\LaTeX$ auto completion/suggestion for the $\LaTeX$ users?
b) If somebody is posting in plain text, suggest (and possibly auto insert) $\LaTeX$ tags. This is very much possible and a very good feature to see in the stack exchange community.