Before you start pontificating about other passengers, get some experience of a kidney condition. Bladder control is often extremely difficult, and pressing needs occur with very little warning. There are far more people with this issue than you may think.
But in any case, as others have said, anyone who is hydrating regularly is going to need to go regularly, probably with some urgency.
Not sure though how this impacts the subject matter. Such problems (related to health related urgency of urination) exist regardless of number of lavatories in operation and by definition are more common in Y where passengers will typically still have a lav ratio worse than J even with inoperable lavatory. The issue of inadequate lavatory numbers is real but different problem but isnt really the subject of this thread.
The crux here that I see is that passengers have a right to expect lavatories to be operational - and that right exists independent of our individual needs. Indeed the person with bladder problems is often more equipped to avert and manage these difficulties than the average person may be.