Recommend dual-channel memory
It's popular to say "hurr durr only 5% difference in benchmarks" but the reality is that running with a single memory channel can really create a bottleneck, especially on the AMD FX CPUs you're recommending, which have a very weak memory controller.
You're foolishly doing something for no reason which can cause stutters (and thus provably does impact minimum framerates in games) and sap performance from streaming applications which don't use the GPU (CPU-based video encoding, which is still preferable due to higher quality than GPU-based encoders.)
Why not avoid it? 2x4GB is not significantly more expensive. It's pointless, foolish, and childish to recommend 1x8GB "because it usually doesn't matter".
It usually doesn't matter if you wear your seatbelt. I'd still prefer to do so.
I will always attempt to recommend dual channel RAM when it is not a significant amount less than dual channel, however I believe you are overstating the benefits.
Granted it could make a difference in some cases but it is unlikely to make much of a difference at all in terms of gaming performance which is what choosemypc aims to maximise.
That being said I believe the crucial has come off sale and will shortly be replaced by a better option within the build generator.