Suicide in Middle Earth

[William Cloud Hicklin]

Miriel (Feanor’s mom) is not condemned for committing suicide

Ah, but that's not really true. In later years, the Wise considered her choice to have been at the root of Everything Bad. Even at the time, Mandos predicts that no good will come of it. Laws & Customs Among the Eldar and its associated texts are pretty hard on Miriel.

It is however the case that 'suicide' for an Elf means something rather different than for a human, as the Elf's life within Arda can never be ended. The fea may be houseless for a time, and confined to Mandos, whether the hroa is physically destroyed or merely 'dies of grief:' but these are 'seeming deaths,' because the Elf never leaves the World.

In fact, since Elves can 'die of grief,' it would seem that 'suicide' by violence isn't even necessary for them; they're capable of 'suicide' by will.