They just stayed there without evade him, they could had to move to other pit and if hinder keep bother them he for sure deserve get warned.
They did nothing than stay there and never tried or even did any effort to get hinder off from there.
But at this way you take the rules, what happend if every place is occupied? so hinder cant level at all? At the same way hinder had nothing to do blasting there, same monsters dont have tw name on them, so hinder is free to blast also.
I dont see how he ruined those players lvling, there was lack of blasters, check the monsters they where unable to kill them so Hinder blasting there give the chance to those TW to get more LBs.