Indeed it is, and sadly all too common in a age where we should be more understanding.
I completely agree with you Noblehead, but not all circumstances can be accommodated, and there comes a point when it is possible more employees' livelihoods would be at risk, if absolute and ultimate "protection" were in place.
Don't forget, in many circumstances the employer will be upset to lose a decent employee.
I have had to manage people out of businesses in the past (not for diabetes, I might add). I have also been forced to spend thousands of pounds on desk and chair adjustments for (in the the case I have in my mind's eye currently) who felt the DIY work he was undertaking on his home was more important than being a fully functioning employee in a specialised business.
I have also, at the requirement of Occupational Health, been directed to fund a knee reconstruction for an employee who had been instructed by a specialist to desist from participation in contact sports, pending treatment, but the guy went on to wreck his leg, in a big way. As it transpired, the directive was made on the basis it was cheaper to pay for the surgery than pay his salary during his time off sick, awaiting surgery on the NHS. That person was based in a 10 story building and could not be allowed to work, in the building, on crutches, due to an evacuation risk, should an emergency arise.
That last one took some selling to another employee waiting for something equally needed, but where she was able to attend the office.
It is also sadly true that sometimes circumstances play into the hands of an employer who would like to ease someone out.