First of all, please forgive my bad grammar and how awkward what I wrote is. English is not my native language so I know there will be a lots of mistakes.
Also, prepare for a long tirade.
Is really a 'generic evil jerk isekai dudes' as
@saifors said. Yes, there are stupid people everywhere. Yes, there are really, reaaaally stupid people in this world, so stupid that is hard to believe. Even so, when survival is at risk and you face death as close as they did (even the delinquents where scared as heck), many times those stupid people are the first ones that tend to shup up and obey others if they believe that will allow them to survive; more so people like them (delinquets and gals) that feel the need to be part of a group so they can feel secure in their social lives.
I could have believed their attitude if the delinquents had felt their pride was being trampled by the others after the incident of the goblins, but so far (as manga and WN narrates if I remember right) nor the geeks nor the rest of their classmates seems to be belittling them, just asking them to cooperate with the rest of the group so all of them could survive.
The gal girls have even less motives to be arrogant after what happened. Yes, they could have been entitled b1tch3s back in their original world, but at this point they must know that: 1.- They are not in their world anymore (Magic, Monsters, etc). 2.- They don't have the skills to survive by their own (fighting skills or survival skills). And 3.- The people that have the knowledge and abilities they need to survive are the geeks, as they showed by saving the life of everyone (they were the first to act, motivating the rest to fight back too). So, no matter how stupid a person can be, it should be obvious that antagonizing the people that can help you survive is a really bad idea.
There really are not any motives nor logic explanation of why they still have that attitude aside from the author need of some villians so the MC can defeat and looks more virtuous in comparison.
Ah, don't get me wrong, I still find this story more or less interesting, if anything because I want to see where all this goes. It's just that I have become a little tired of this particular cliche of 'A group of people are summoned and only the MC and his future harem members are good guys while the rest are absolute trash'. It really hurts too see it so often.
Ah, thanks for the chapter, translator-dono! Really appreciated!