Yeah, that's what I'm thinking as well. However, I still find it surprising that a Core 2 Duo without an integrated memory controller can produce some 30-40 % lower memory latency than this thing.The spotty support is a disappointment, I will acknowledge that.
However, the rest is fairly logical because its a smaller core processor with much less out of order execution resources and a memory subsystem designed for efficiency over pure performance. You will never see a lower class processor perform equal on memory performance compared to a higher performing one. Architects surely realize this and putting a memory controller that's too powerful is like putting a McLaren engine on a Miata. Both are considered sports cars, but aimed at totally different sectors.
4 Goldmont cores with the System Agent equivalent block can fit in a space that's roughly equal to the area of a single Skylake-class core. The chip is very respectable considering that.
Anyway, this already low performance probably lessens the effect of low latency RAM.
EDIT: By the way, I created a support discussion on Intel's forums regarding support for the 2400 MHz HyperX memory. I don't expect much to come of it, but you never know.
EDIT 2: Interestingly, the company I bought the HyperX memory just called me up and told me they'd replace the memories for me. I took a quick decision to keep them anyway, but thanked them for the good customer service. I figured I might as well give them a go in the NUC and otherwise, if they don't work, use the Crucial sticks I mentioned earlier. The difference will be negligible anyway.