AVX2 is a set of instructions and AMD supports them. How they support them is a different question. Does Intel not support AVX512 because their processors run at a lower clockspeed when they execute? There are more and less efficient ways to support an instruction set.

AMD decided that consistent clockspeeds were more important than wider units. They decided that most users won't use enough AVX instructions to overwhelm the AVX unit (especially with consistent clocks), so there was no justification in ballooning the die size and increasing power consumption without a decent payoff.

https://en.wikipedia.org/wiki/Advanced_Vector_Extensions#New...