They are unbearable, far worse than even the most partisan and "destiny" driven Djokovic fans ever were. The latter had an almost deluded belief in their guy Djokovic's future, but they still had a certain respect or weariness for Djokovic's rivals as well. The Sinner fanatics don't seem to respect anyone outside of Sinner when it comes to what Sinner is "going to do". The way they acted before Rome, that Sinner was going to just dominate, and then Alcaraz beat Sinner in Rome and they shut up for a short time, but then it all came back at the French Open, where Sinner was called "better than 2008 Nadal" by some (FFS), and then Alcaraz beat Sinner again. When Sinner did beat Alcaraz in the Wimbledon final, Alcaraz is basically trashed as if he's never going to win a major again. It's just way over the top.