Whether you call it a disease, condition or disorder and without wanting to scare people sh**less, diabetes should not be underplayed.
To say something like 'Dont worry Diabetes is not a disease it is only something to be controlled' sounds like it is something easy to do and not serious.
It is a very nasty disease/condition, which we we are all working very hard to control, but some people with the best will in the world don't succeed as well as others, and if they don't manage it, then they may think it is their fault.