No, no they're not. Yes AMD support a lower overall RAM speed than Intel CPU's but buying a suitable kit when building a PC should be the same as any other expensive purchase you make, you research what you are buying and don't just throw money at it cause "dats the fastest and mostest xpensivvvv/cheapest so it must be de besssssttt"
XMP is an intel technology and whilst it is good and all, if you don't do some basic homework on what parts you're buying and if they're compatible, how is that down to AMD? for AMD there are recommended kits of DDR4 RAM and tested kits for each and every motherboard that you can buy, but as we see with all the "My Ryzen motherboard doesn't run my RAM at their rated speed" threads people don't do that, they buy a CPU and motherboard and any old RAM they feel like throwing in there without doing so much of a smidgeon of googling about compatibility and complain when it doesn't work right. The fact that AMD motherboards support XMP is a plus point, but building a PC is not the same as building a lego set and if you have little experience in doing so but just wanted to try after watching 1 YouTube video on "how easy" it is then you really should stump up the extra $50/$100 bucks to get someone or a company who has the required knowledge and experience to do it for you and then just use your consumer rights to return it and get it sorted instead of wondering why your Corsair LPX 3200 won't run at it's rated speed on your Ryzen build.