I don't think they "realize" what they are watching, it is just that unless the viewer is a) a theatre fan or b) planning on visiting New York the nominees and winners don't hold much interest. The musical numbers do to a point but for a non fan unaware of what is on Broadway now scenes/songs from MEMPHIS, AMERICAN IDIOT et al. will not hold any "must see" appeal.
As a theatre fan, however, don't you want to know who wins (whether you agree or not?)
I can understand avoiding awards shows if you don't care about the subject. I rarely watch the Grammys, never watch People's Choice or Golden Globes, and will usually have the Oscars on in the background, but the Tony Awards I actually sit down and watch. The telecast offers more Broadway coverage in one night than we get the rest of the year. And it's fun to see the numbers from the nominated shows. This year I will have actually seen all the nominees!
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com