hey there this is a great question.
i worked in a nursing home for 2 years doing activities while i was in nursing school (am now an RN).
I too, at the beginning, felt guilty but it isn't cruel if used correctly. for example we used to have patient's constantly trying to get out saying stuff like "i'm calling a cab, i'm leaving." we used to say things like "we called the cab for you, lets go wait for the ride in the dining room." Once in the dining room we could start an activity- cards, coloring, etc. after a few moments doing the activity they usually forgot about wanting to leave. if you are able to assist the patient in becoming happy again then that is a good thing