Yup, this is a hard requirement for me. When someone says they pay competitively or market rate, it's usually low. When someone pays well and doesn't give numbers, it means they're stupid (to pay well and not pitch it) or they're underpaying someone quietly, which is a red flag.

The processes are usually too long to go through without a given number.

Some context from the hiring side: not all employers can afford to pay top dollar for mid-senior level candidates, so the business proposition in those cases tend to be geared towards growth (i.e. either "grow the company and the employee together" or "I'll just gain some experience with this employer and job hop when my resume looks more solid"). This is more common on the lower end, which appears to be the case for this job description.

For more senior level, I agree. Senior level candidates have a lot of leverage and it's generally a bad idea for an employer to be a sneaky lowballer. Interviewees talk and job interview reputation can be a dealbreaker for many potential candidates before the process even starts for them.