I am sorry, but I disagree with you.
First of all, geographically, the definition of North America is always a problem. Some people consider that it only includes Canada, USA and Mexico and others extend the definition to include all the countries through to Panama, just as you suggested.
Second, a lot of the birds that are discussed in this forum winter in Mexico and spend the summer in the US or Canada, so not all of the queries from birds seen in Mexico will be out of the area of expertise of most of the American and Canadian birders.
Third, when the forum was being rebuilt a couple of months ago, I specifically mentioned this possible confusion with the North American forum, and since no one raised any objections, I understood it was fine to post requests of help to ID birds seen in Mexico in this forum. https://forums.whatbird.com/index.php?/topic/56-birding-category-topics/