Most of what they gather is useless, they're just looking for better ways to target their advertising.
People should be careful to avoid posting things they want to keep private, but avoiding social media does exactly nothing regarding your visibility.
I used to have access to a report that would tell me everywhere you ever lived, everyone who ever lived within twenty blocks of you, every kind of licence you have or ever had, your criminal record, everywhere you went to school, your entire family tree, your credit rating, the list goes on.
I'm not sure what you're trying to accomplish with your disinformation, but I assure you, anyone malevolent and industrious who wants information about you is going to get it.