We all are in our mid 20s. None of us have been done with school for more than 2 years, so naturally we live with other guys our age.
Having roommates and making money are not mutual exclusives.
You have put me in the awkward position of partially agreeing with TridenT.
I am approximately your age, and out of all the people roughly my age that I know (coworkers, people I graduated with, myself, etc.), only a handful opted to have roommates after graduation. None of these are hugely wealthy people, although they are all reasonably well-off.
Not saying it's insane to have roommates, but it did strike me as odd, especially since your roommate could easily afford to live on his own. And honestly, not having roommates has substantial perks (for instance, not having to deal with people like your roommate every day).
To the original point, your roommate sounds like a douche. If the following is accurate:
He often will act one way towards a person, then the minute they walk away he will express how he really feels. It is very common to "put on a front" for people in this manner.
... and extends beyond the basic sort of politeness that is normal (and somewhat necessary), then that is enough.