I heard about this story, apparently it was biblically wet and he hit standing water at 130+ on the TG track - car sat up on the water, span and he finally stopped somewhere near Madrid.
No defence from me, a RWD is harder to save, everyone knows that. FWD you simply stick your foot down, point at where you need to be and prey. Watch the BTCC, the ebay 1 series didn't have any issues in the rain.
I'd take a punt that he had all the driver aids off (something you can't do in the GTI) as they'd no doubt been doing some spectacular TV broadside drifting.
In day to day driving, even in Sport+, it's no more difficult to control in the wet than a FWD car, so long as you don't treat the throttle like an on/off switch and understand weight transfer. I do get how novices can easily get into a lot of trouble in fast RWD, mostly because nobody ever gets exposure to them any more... everyone learns in safe little FWD hatches these days, and then thinks 4WD is the answer when they want more power. I remember when you could buy MKII Escorts out of the Loot for a few hundred quid and then spend all day hooning on Stretton Airfield, pretending to be Ari Vatanan. Ahh, good times.....
People can peddle a GTI or an S3 in the rain on back roads faster, simply down to confidence. They have no more lateral grip, they have the same tyres, they have the same weight pushing down on them... it's all to do with confidence and experience.
I did a track day recently in the pouring rain, and I'm sure Beddie will testify (as he was there too) mine was a pussy cat, and was easily doing 2:20s - a very respectable time indeed. Likewise my old 135i, that did Spa, Oulton and Rockingham in the rain... I'd say that was a little trickier than the new one though, bit quicker to step out.
I can't wait to see the episode, his face should be a picture!!
Evidence of me not dying in RWD.