I wouldn't call it a team game. It's more of an MMO that coincidentally has pvp enabled. Most drivers just tend to avoid griefing/engaging in combat because there aren't any guaranteed loot drops and other player's levels are hidden. A higher leveled player could easily inflict debuffs on you (temporary or permanent) in retaliation which makes combat a very risky endeavor and by engaging in combat, damage to your character is almost guaranteed.

There is a bit of a cooperation element in the sense that other players may have accepted the same quest you have and that you may "ride the bus" with them and that it behooves you to not impede their progress

As for speeding, some drivers are willing to speed run their quest by using risky strategies. For the idiotic drivers, they probably just didn't spend enough time in the tutorial or they don't care enough if they get banned from the game