Do you find blow jobs demeaning?

Those same guys will generally NOT find it 'demeaning' to go down on a girl: who said men are better at logic than girls are? ;-)
Just a few random thoughts:
this wonderful man's penis"
You may feel about it like that ( it's even quite normal!) but I'd be uneasy about men who thought about themselves that way.
IMHO it's (again) connected to the 19th century Victorian 'morality' that still is very present in our society.
It's absolutely not illogical for a man to feel guilt when asking for it: education, 'morals', girls and society taught him for years that it's nothing but a penis and that he really should hide the [***] thing from everyone or else get thrown in jail among the perverts.
It may be hard to get over that education unless he's a macho, of course. There comes the 'domination thing'.
Thus a man who really likes a woman might indeed think twice about asking for it. (for generations it was 'something no serious woman would do' and men went to prostitutes to get it)

Another thing that's maybe best initiated by the girls. The guy might even say them he doesn't want it tough he's been secretly hoping for a long time. If he's heavily influenced by education he might convince himself he doesn't really like it, which would (partly?) account for the majority of men unable to get an orgasm that way: it all happens between the ears.
(very similar to the ideas circulating during the 1800-1960 period, when 'serious women' weren't supposed to enjoy sex)

Mankind (M/F) still has a long way to go.

If a guy goes down on a girl is that demeaning? no way

If a guy goes down on a girl, is that demeaning? No.

It most certainly is not something demeaning when you are doing it out of affection for the person receiving it. I fully enjoy doing it to my boyfriend and bf's in the past. Only possible way I could see anything demeaning about it is if you are being forced to do it to somebody and if that would be the case there are some other serious issues also.
I also believe that there are more girls giving head than guys going down on us, not the other way around as you seem to think your friends believe. Where does this dominant crap come from? I don't feel dominant over my guy, nor does he feel dominant over me and thinking of my friends at the moment I can't think of any situation where dominance by one or the other exists. That dominant thing sounds a bit creepy except in role play of course.

Giving head is NOT demeaning. If the attitude and behavior (of the guy OR girl) is demeaning then it is demeaning but the act is not. It is what you make of it. All sex is an opportunity for connecting, sharing, pleasing and having fun. Any sexual act can be demeaning if there is no respect or love (or at least caring).

Here's a switch though: Many couples like a certain amount of role-play in their sex whether it is conscious and on purpose or subconscious. Most sexual fantasies (men and women) involve an aspect of role-play--being someone that you are usually not, even if it is very minor. Many couples like to role-play a little bit of sub/dom flavor into their sex lives. According to many polls and studies, the most common sexual fantasy for women is one in which they are swept off their feet and "taken" and to some degree overpowered or forced. Out of context, most people would look at this behavior as "demeaning" but in these cases it is welcomed and consensual.

Many couples perform these types of sexual acts with complete respect and love for each other but embrace the contextual submission or domination that they are performed with as an erotic enhancement. Bottom line is if you are having fun and being willing to let yourself have fun, then whatever you are doing is acceptable as long as no one is being hurt on any level against their wishes.

If a guy goes down on a girl, is that demeaning? I think not.