Of course these mindless sheep would completely follow the goddess who assaulted an "S-rank" hero out of blind ignorance instead of fear; it would have been a much more interesting story if they class had all abandoned the main character, but had done so out of fear after seeing what the goddess did to one of the most powerful of them.
I mean, I get that they author wants to write a revenge story, so I get the way selfish way the characters acted, but I really do think injecting the element of fear into the class would have made for a much more interesting story and would made a reconciliation even interesting. Just imagine the class goes along with the Goddess because they're terrified they'll be smacked down too, but then when the main character tracks them all down, they tearfully apologize for their cowardice and all agree they want to take out the goddess because why the fuck would they want to be summoned to a world against their will in what's basically a case of multiple kidnappings at once?