If you ignore the ASA or tell them to fuck off, they will do bad things, like
They might also take out an advertisement on Google so someone sees a message when they do a search for your blog/business/youtube channel indicating that you've told them to fuck off.
I think people should be clear when they show sponsored products, that's about basic integrity and ethics, but the ASA can make bad decisions. They aren't a government body. You can tell them to fuck off if you want to. The worst thing they'll do in many cases is tell people that you've told them to fuck off.