Ithink there are several reasons:
The Jade Goody reference has given the name a definite pigeonhole, for want of a better word. Not everyone identifies with her. Names are deeply personal and people need to identify with a name to really like like it. If they associate it with someone for whom they have no affinity (or a social group they do not relate to) it will alienate them. We all know names that we consider to be too posh, too downmarket, too boring, too trendy, too pretentious, etc. Whatever you chose it would enevitably fall into one of those categories for most people!
Jade is not a particularly unusual name and hasn't been, really, for 15 years or so. People have just got used to hearing it.
People only tend to say 'Ooh, what a beautiful name!' if it's something very unusual that they have never/rarely heard, and that immediately strikes them as lovely -assuming they don't hate it of course! Most new or unusual names take a bit of getting used to until they become sufficiently popular that we are no longer alienated by them.
I hate it when I'm told a baby's name because I am difficult to please and rarely impressed. I feel bad saying nothing, because it's kind of expected, and new parents are always thrilled with their own choice, but I'd be insincere if I waxed lyrical for the 99th time over Amelia or Luke.
I was a momentarily stumped for words when I recently met a baby girl called Kenyon though...... Apart from anything else everyone will assume it's Kenyan, like Libyan or Syrian. Bizarre. Still, horses for courses as they say.