Cc, yes, I've seen the reef. Part of it, anyway. Snorkeled on it, spent the day there, and listened to marine biologists talking about what is currently causing concern. (Marine biologists who were there, and also subsequently, on various documentaries. I don't believe all of them are crying "wolf".)
Things ain't what they were, apparently, years ago, when a pollution event -although horrid - did only temporary damage. I don't remember all the details, but many different ongoing events, including water temperature change, the slowing of the currents, overfishing, and increase of UV light, are collectively and cumulatively, having quite a bad effect on the reef's health.
I was led to believe that although it is not fragile, it is, in our time, in fairly worrying trouble.
A bit like some cancers. By the time the symptoms become obvious, it may be already too late.