To be fair, some of your information are public because they are required by laws. For example, your home ownership. As soon as my parents bought a home, a mail came to my new home address addressed to my family.
Most people who actually send junk mail to us are via agency, and these people are small business owners.
Also, some junk mail are delivered via cheap labor, actually walking to people's home and drop off (local supermarket for example), not via USPS. So that's another "direct mail marketing" and yet a lot of people enjoy them!
I just throw junk mail away. My philosophy is that as long as they don't kill me I am giving these small business owner the opportunity to grow.
The only kind of junk mail I don't want to receive is the annual yellow page book.