The vast majority of people don't run their own DNS server, or have any control over the DNS server they use. Most people use their ISP's or organization's DNS

The vast majority of people don't run their own DNS server, or have any control over the DNS server they use. Most people use their ISP's or organization's DNS server, and have no control over it; instead, it's something used against them. In many cases, that DNS server may do some combination of tracking, redirection to ads, or other things that make it undesirable to use. DoH eliminates one of the last major unencrypted protocols on the Internet, and instead uses an encrypted protocol to talk exclusively to the intended server without the possibility of interception. If you want to talk to your ISP's DNS server, you're free to do so. But that should be your choice, not your ISP's.