To people annoyed the author making the guys look bad, it's realistic: horrible people hide behind nice personas. So when things went well, those three guys were acting good and flirting with Alicia, but once things got dire they started to show their true personalities. The only reason they don't do nasty stuff to Alicia is because she's stronger than them, but even so they had the audacity to defy her authority, that's a red flag.
And this chapter served to show why Old Man's advice is sound: Suzu party (a group of nice people) were instantly wiped by much stronger monsters. So yeah, just because you're an adventurer doesn't mean you don't have risk your life recklessly, specially in a fantasy world, where monsters can wipe armies.