I'd be very interested to see this but if it's training material for the top 0.01% of refs I think "well known" is a stretch.
If English refs have been specifically intructed to caution for this then I can't blame them.
The good book absolutely does not require a caution, and given the fact a foul tackle is now almost always not a caution, caution for handball is completely inconsistent and illogical.
Ive received that instruction in online training seminars as a grassroots ref in the US. So maybe your ire should be sent towards the training provided by the FA of County FAs.