I don't think the point was whether or not the music is difficult to sing but that whatever health problems she's having (which are really none of our business) are causing her to not be able to sing much of anything while she attempts to recover.
It has been said many times that this is beyond her control and she certainly isn't wanting this to happen, so leave the poor girl alone. She seems to be having enough problems without people she doesn't know dissecting her performances and speculating about if she's a diva.
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