Anything related to manners is specific to a country or region. These things just aren't universal.
I'm guessing that 'not' isn't meant to be there. The Spanish and Italian don't tip as a rule as, like you say, being a waiter is considered a profession.
Same in Spain. Thanking a waiter is really not the done thing but I still can't help myself even though I've heard it's a strange thing to do. It just feels too weird to not acknowledge that somebody has just brought you food or a drink.