Consequences aren’t the only thing that cause people to act they way they act. It’s certainly one reason some people don’t do certain things.
One reason Homelander is the way he is is because how he was raised. If tomorrow I got all Homelander’s powers, I wouldn’t instantly become a psychopath. I mean it might occur to me that any action I might take, and no one could stop me or punish me. But as Homelander observed (at least in the prior season, I’m not entirely caught up) that alienation from his fellow supers is actually a consequence he deals with.