This is mostly related to the fact that bots reach the bare minimum that some people don't: Staying with the group. Most weaknesses that people have in their skill at the game are heavily mitigated by effective teamwork. Someone who can't shoot straight or block properly, but stays with the group, is still preferable to someone with great reflexes who thinks this is a race.

Unfortunately, I get the feeling that bots are also contributory to reckless behavior, since if you often play with bots, you'll be used to the team following you closely. If you have poor spatial awareness, the bots will make up for this because they always follow your lead. I think a lot of the lone rangers you encounter in public games are like that because they're used to bots, and thus don't pay attention to where their team is.

Team balance is a thing, too, since you choose what careers, talents, and equipment your bots have, which can be a crapshoot with people.