FYI: 'Please don't insinuate that someone hasn't read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."'
But he didn't read the article in full, and made an uninformed opinion that is now at the top of the comment section... Bad comments need to be put on blast. Save your rule book for something more inane.
"The article mentions that." would still be appropriate then. Rulebook still good.
A better way, in this case, would be "It seems that you might have not read the article properly, as ... "
Why? It's just closer to antagonism, which is what the guidelines seem to seek to prevent.