If suicide, I doubt there even is a clear motive (of course, forced hormone treatment is going to play a role in suicidal thoughts). It will be multi-faceted and reduction to one thing (be that the treatment, or something else) will not do full justice to the complexity of suicide.
> Sometimes they're trying to protect their families from their feelings of despair.
I think the cyanide apple was there to provide the possibility of an accident, for Turing did not want to hurt his mother with a definitive suicide. Or maybe he took his lonely love for fairy tales way too far and expected to awake to a kiss from a beautiful prince. The latter is no less a speculative invasion of his private life, than taking his sexuality or treatment as defining of his scientific legacy or suicide.