This forced upgrade for newhires can be fixed, but I doubt many here would like the fixes. Just to name two ways to fix it:

United is losing CAs. How to retain CAs? Increase the age to 67. Those of you are in adamant opposition to NHs being assigned unfilled CA slots should be out there vigorously supporting age 67.

United has too many career WB FOs. Force those that go NQ for landings into the first available landings class or be placed on unpaid status. There are some bunkies that have avoiding landing class down to a science.
Getting those WB FOs requaled quickly will reduce the number WB FOs needed and will make the job less desirable for some, pushing at least a few to take NB CA vacancies.