Why where the Teleri Ships Irreplaceable?

[Naaramare]

He dared to be great.

He dared to swear an oath that killed all but one of his sons and drove the last utterly mad. He dared to slaughter his kin--and if they were wrong for refusing him the boats, he was a thousand times more wrong for raising sword against them.

Somehow, I don't think his particular brand of "greatness" is really something that should be emulated.