In my (limited) experience hiring Colorado employees remotely, we had to make several different job postings with various ranges to make sure we didn’t exclude any possible applicants for having too high or too low salary bands. If someone applied for the $200-$300K job description but didn’t have the right experience or performance during the interview, we could offer for them to “reapply” to the $150K-$200K job title and pick up there. It felt like a lot of formality with no real benefit to either side.
The Colorado law also doesn’t stop at the job listing. You have to follow specific procedures for various things after the employee is hired, too. I could see companies excluding Colorado just to simplify their operations and avoid opening themselves up to another state’s different employment laws.