if he is reffering to the PSUcultist PSU tierlist, it doesnt.
in fact it puts it in the Multirail/switchable category compared to singlerail on the AX. Which is "higher" on the list, but also just better at the wattages these PSUs are available in.
they are both guilded, but thats just because the tierlist doesnt really differentiate above Bitfenix Whisper M quality wise.
it doesnt do that tho. And if you were to ask, they would say the AXi is the best PSU in corsairs lineup (and on the consumer market in general). The AXi being in no way comparable to the AX, as the AXi is just way better.
and as mentioned earlier, the HX and HXi are both rated higher on the list aswell, due to being in the Multirail/switchable section.