That’s what JEDEC has validated the integrated memory controller on those Intel CPUs.
But you can use faster memory if you’re on a board that supports memory overclocking. The XMP profiles are a combination of settings the RAM manufacturer has tested that SHOULD work. Or, at least, the memory chips are capable of those speeds and access rate.
Point is: everything past the JEDEC standard is considered overclock so it’s not guaranteed to work. But it has become reliable on the Intel platform so if you buy a higher speed kit that’s supported by your motherboard it will probably work without any problem.
Going for even faster RAM speeds makes the compatibility less and less probable.