His entire family could have been wiped out by Truck-kun and I still would feel no pity because his actions are still HIS actions and he should get penalized for behaving the way he did. This is an issue I have with a lot of MCs they're too nice. I'm not saying the douche needed to be beheaded just abandoned to his fate.
I totally understand where you're coming from, and even found myself griveing over 'overly kind' MC in most isekai manga. That said, I think this one can be an exception situation. First off, the 'annoying brat' is simply desperate and immature. Desperate situation calls for desperate measure. Second, the 'annoying brat' never tries to put physical harm toward MC. He's simply trying to take his job in order to save himself. While I argue that it's not noble at any point, he is still within the realm of forgiveness, at least to my standard. As far as I can recall, he never threatens to do physical harm to MC or anyone else. As far as I can tell, the only extent he has gone was to demoralize MC by calling him stupid due to his grades being 51 and he himself got like 83.