Longstanding labour shortages in the relevant police departments that have probably been aggravated by current nationwide labour shortages, combined with professional cycling not exactly being high on the police's priority list which means they've repeatedly pulled/tried to pull out of committing workforce there.
I can see the issue there of course, but not really how it let to the decision to not allow those "C1" qualified policemen to supervise cycling races anymore - instead it now needs a special qualification (only very few seem to have), according to that article. Maybe some bureaucratic or legal reasons played a part there as well?