This is an article on Tennis.com about the incident. Paul Annacone said he should have let it go, Brett Haber said it's a slippery slope.
I agree that Shapovalov has anger management issues. He was also points away from losing the match, anyway. I'm not sure what the letter of the law is in terms of shouting an obscenity at a fan, provoked or not, but I can almost guarantee you that it's vague. We've seen players be horribly abusive towards umpires in the same way, and get away with a code violation. There are a couple of points worth discussing here: A) is an obscenity directed at a fan more heinous than one directed at an official? If so, is it because they're the paying customers? Because the fans seemed displeased to have had the match stopped at that point. It deprives them of the tennis. Due to one rude fan. B) These violations/DQs are not handed out evenly. It depends on the umpire and the tournament director. C) The ATP is notoriously toothless and spineless when it comes to defaulting players on obscenity charges, or worse. Rublev's DQ was overturned earlier this year, when it was deemed to have been unfair, and it probably was. That one definitely deprived the fans of the resolution of a tight match. In that match, Bublik, (I think it was?) also petitioned the umpire to let the match continue, as Shelton did. A couple of years ago, when Zverev directly attacked the umpire's chair at the end of his doubles match in Mexico, he was rightly defaulted, for a much more aggressive and egregious act, but he wasn't further sanctioned, and went on to happily play Indian Wells. Where is the consistency?
IMO, tennis has to get over clutching its pearls a bit with the swearing. And even with crowd interaction, to some degree. It's a spectator sport, and its school-marmishness made the spectators unhappy. Same as in the Rublev match. That's not good for the sport. And just wait until they say they were wrong and reinstate Shapo's points. I think they should. It's better for the sport. Shapovalov has his own issues, which he should work on, but a code violation would have sufficed, at this juncture of that match.