It's possible the idea "Bob Ross was a PTSD vietnam vet" hit more than one creative funny-mind, and there's several versions of this out there since so many commenters have brought this up saying that they remember it as a standup.

Still haven't found the skit I remember.

Yep, there are so many things wrong with this ad I'm amazed it made it through production. It offends every religion involved, and for what? The Buddhist monk is a materialist, the priest ditches his congregation, the Muslim wears the colours of Israel and the Rabbi blames all the other guys for being late. Meanwhile, very few people spot that he's actually wearing a dark yarmulke the whole time, and simply changes before the game, so the change-scene is interpreted as if he finally puts one on... Making the stadium a more revered place of worship than his own Synagogue.

Saatchi should count themselves lucky the offense over this one is going to be drowned out by people mad at the Ram Martin Luther King ad.