I don't think that "looking down" on someone with a less-than-technical degree is at all what we're supposed to be doing, nor is that the message.
Mike's message is that following your dreams is OK, if those dreams are in a generally good direction. I read that he also implied that there's much to be gained in looking, "not for your dream job," but instead for opportunity. Opportunity is sometimes disguised by hard work, and sometimes literally, by crap.
I get the feeling that 20 years ago, Mike Rowe's dreams and passions didn't include his own TV shows and giving graduation addresses to college students, but he saw an opportunity and one thing led to another...
The “non-math/science” reference ties back to other comments about people’s majors in other threads. Probably didn’t make a lot of sense in this one.
I actually remember Mike Rowe doing infomercials about new housing developments that were springing up all over Maryland.