I've noticed this too. Why does amazon have aboutamazon.com and Google have developers.googleblog.com? They literally have their own .google TLD but still choose this weird domain.

Same with local governments. They love something really random like <countyname>proptaxpayment.org instead of treasurer.<countyname>.gov. It's exactly the kind of domain you are told to watch out for, but actually legit.

A common scenario I've seen in the case of local governments is that a department (e.g. the Assessing Department) contracts with a vendor to run the website and has no idea how DNS works, and the vendor defaults to registering new domains for their clients since that's the easiest when dealing with non-technical clients. Texas alone for example has 254 countries, the vast majority of which are very small and have effectively no full time IT department, so when these vendors are engaging new clients, low IT expertise is the norm by volume.

The local government itself may have an IT department, but they may not know how to create a subdomain, or even be aware this contract is being made and the site is being set up until after it's announced to the public.