I can’t work out whether the audience in the background is disinterested or simply superimposed.
My guess is that the folks you see sitting stoically in the background are the parents of the shrieking girls who are up near Garrett. That’s not really a video, per se. For the most part “music videos”, as we know them, did not exist prior to MTV. This is just a clip from a pop music show. This song was a hit in 1979, a couple of years before the advent of MTV.
There are really two questions here. I think ShibbOlethis right on regarding the audience. As to whether the video is dreadful? Yes, yes it is.
Sorry- I used the term video rather loosely. I should have used clip or such.
I am grateful I was never a teenage idol of the 70’s with young girls trying to lay me.
Really.
Yeah, can you imagine how expensive it must have been to replace all the clothes that get torn off? No thanks.
Que? There’s a lot of pre-MTV videos. Queen, The Trogs, The Beach Boys, The Kinks, and a lot of other shot short films for their songs that weren’t just tape of performances.
Hmm, Leif Garrett is circumcised; how about that? 
Yeah, that is a pretty dreadful video. I loved the irony of the song being “I Was Made For Dancing” and Leif not doing much dancing, though.
That’s LEIF-TASTIC!!!