i saw new bounty projects that have allocation worth of 1000dollars and they even have separate campaigns, why are people promoting such projects?
Sheer desperation. It's the same reason why new members come here to work for extreme low wages, will do all the work up front and hope they dont get scammed at the end, and its why you'll see these same people performing mindless tasks such as entering captchas or bumping threads, for which they probably do literally get paid pennies.
And where does that desperation come from? People from poorer countries who are not able to find work or can't work for whatever reason. To someone in a first world country these bounties aren't worth the effort usually, but for someone who is dirt poor they can provide a living wage. It's incredible to think about that, but its true. Why do you think so many people apply for bounties and everything else here? Generally it isn't for the love of crypto but to feed themselves.
I concur with you op, bounty hunters don't have a lot of respect for themselves and their worth, but I understand where they're all coming from.