Board Thread:Help desk/@comment-11129891-20130708185234/@comment-8168904-20130709221232

Correct grammar subliminally (or consciously, to an extent) shows the reader that they are reading a credible source of information, not a page made by some knuckleheads who barely took the time to make it.

In other words, grammar shows deliberation in the page.

It's also easier to understand.