https://www.engadget.com/2017/05/19/destiny-2-pc-dedicated-servers/ To make matters more annoying, it is also coming out after the console version...
On this note, I would like to mention that They Have Dedicated Servers Fully Developed. And they will be part of every single client. They only decided not to allow you to run that code without first starting game and being present in match. So, no matter how many excuses they try to make, it is BS. They should at least clearly say that it is their choice.