He spent over a hundred hours practicing the DLC, but I just fail to see what that has to do with the event. Speedrunning is his thing, he didn't spend those hundred hours preparing for GDQ only to get shut down, he would have spent those hundred hours regardless because he speedruns as an everyday thing.

Fair enough that can get annoyed over it not being represented though. But I still think cancelling the entire game's speedrun for charity over it is a tad too dramatic. While it is certainly possible to get records at GDQ, that's not the point of GDQ and I would daresay not the spirit of it either. It's a public event to raise awareness and funding for charity, but also to introduce new people to speedrunning and show off your skill. Sure, it may be incomplete but he is literally ruining a chance to get more people into DS3 speedrunning, showing off what he is capable off and also removing a great game from the event that could have lead to more people watching the event, and maybe even donating. It's gross overreaction and part of me genuinely feel he only did it to try and pressure them into letting the DLC be part of the event.

If he simply don't have the time and would rather spend it trying to set records, that would be a better excuse.