Who exactly threw a temper tantrum? There's no evidence of such a thing. They made one very respectful and professional statement through a lawyer, asking for a thorough investigation before theories be concluded. I would be frustrated in their position as well. Cue my earlier posts as to why, as I don't want to rehash out of respect for other folks on this board.
It's not about stigma or the elite being above mental illness, they are a intelligent group, I'm sure they know no one is immune to mental illness. It has to do with them being blindsided, and knowing their parents, and that if this was murder-suicide, having no evidence to have seen it coming.
As much as you take offence to the stigmatization of mental illness, I take offence to the depiction you have painted of a horrifically grieving family, with a plethora of questions, who are also in a unique mental state equated to grief and trauma. I'm sure many before have reacted in a similar manner when faced with suicide, regardless of their socio-economic status.