Guinness is supposed to be served warm.
The Brits prefer their beer at room temperature, so I’m not sure that’s a factor. 
No way it’s fake. It’s very very likely an internet-only “viral-esque” ad by Guinness. It’s purposely floated out onto the web as “banned” even though it was very likely never intended for television. This isn’t a new strategy. Volkswagen had one awhile back.
What’s with people critiquing that is was like cheap porn? Ya think? Wallpaper, color scheme, bass line, wa-chicka guitar? Think any of that is an accident?