AMD may claim not to validate ECC on Ryzen, but it's working well enough for major motherboard vendors to market Ryzen motherboards with ECC advertised as a feature.

ECC support not being "validated," for all practical purposes, simply means that board vendors can advertise a board lacking ECC support as compatible with AMD's AM4 platform, without getting a nasty letter from AMD's lawyers.

Yes there is a risk to buy a Ryzen CPU with non-functional ECC.

However, I use only computers with ECC, previously only Xeons, but in the last years I have replaced many of them with Ryzens, all of which work OK with ECC memory.

When having to choose between a very small risk of losing the price of a CPU and having to use for sure, during many years, an Intel CPU with half of the AMD speed, the choice was very obvious for me.

Your quote is for consumer platforms (Ryzen) only; GP's statement was that ECC is not well-supported on AMD at all, which is obviously false (EPYC, Threadripper).