I've come across this company - Bridge Corp. https://www.thebridgecorp.com/ https://www.thebridgecorp.com/ that claims to have demographic profiles for over 25

I've come across this company - Bridge Corp. https://www.thebridgecorp.com/ https://www.thebridgecorp.com/ that claims to have demographic profiles for over 250 million people and the ability to target ads to them. I understand the Ad ID component (great write up [1]) but where does the demographic data come from? How do they know an Ad ID is associated with me - and are thus able to target an ad at me? How can you be removed from these types of tracking efforts? [1] https://www.eff.org/wp/behind-the-one-way-mirror https://www.eff.org/wp/behind-the-one-way-mirror