You really hate to see that kind of behaviour. While I don't doubt that every tournament has its share of bad apples who verbally abuse the athletes, it certainly doesn't excuse it or make it any less embarrassing. I do think if it'd been Tommy against almost any other non-Canadian player in that field, the crowds would've been behind him for his first PGA win - especially with him being such a likeable dude. Hopefully he understands it was not personal, but maybe he thinks twice about returning to this tournament in the future.
It's a goddamn shame, too, because it's hard enough as it is to get the elites to commit to this event, especially with its current place on the PGA schedule, sandwiched between two of the biggest tournaments and right before one of the four majors. It wouldn't take a lot for some players to completely stop supporting this tournament altogether and having it quickly become a bottom of the barrel event on the schedule played by a bunch of scrubs.
For what it's worth, on the broadcast you couldn't hear any of the horrible jeers and Jim Nantz and co. were actually praising the fans for the raucous "Ryder Cup-like" atmosphere.
In any sport, players should always be treated with respect and fans that are incapable of keeping themselves in check should just stay home and yell at their TVs. It's such a travesty that Fleetwood had to endure that type of abuse from the crowds, even if it was a small vocal minority of f***ing losers.