I think I remember a comment of B/barbara somehwere, in which she stated she only uses standard capitalization whenever she's writing on behalf of the AMS. I'm not sure whether or not this is a reason to deviate from this site's style so decisively, but I'd recommend she add a note to her profile about her doing so. Also, it'd be good to a notice (or a link to this discussion) when rolling back an undesired capitalization edit to a previous version. To do so, you need to use the [edit] link at the revision you want to reinstate instead of the [rollback] link. You're still effectively doing a rollback, but you can add an edit summary explaining the matter. This way, future capitalizations can be avoided. All this is assuming the not-capitalization is condoned.
In general, you're in line with http://meta.tex.stackexchange.com/questions/340/when-is-it-and-isnt-acceptable-to-editWhen is (and isn't) it acceptable to edit?: Only edit for "Fixing typos or grammar errors" if the question is on top of the list anyways (or if you're editing for another reason already). However, if a question is really terribly full of spelling mistakes, I tend to edit it anyway; I like to keep the Wikipedia aspect of tex.sx in mind, i.e. as a reference site beyond just helping one particular user. So without a reason like B/barbara's, I might well edit a post (of decent length) that doesn't have any capitalization.
