I know it's kind of meta to be making fun of the sort of derpy gun advice you find on the internet via blogs and YouTube videos by posting a YouTube video on a blog, but Yeti is spot on, here.
(It's Yeti, so if your office is not the sort of place where gratuitous F-bombs are cool, you may want to turn the volume way down.)
I've carried ported guns in the past and I can't tell you how many people told me all kinds of "zomg you'll set yourself on fire!" or "zomg the flash from the ports will blind you!" stuff. When you asked them how they knew this, hand-waving ensued. It was just something "everybody knew".