You are using words like "quite a number", "many", and "most" while grouping all AORs and AOEs into one giant class, which is not the correct way to talk about it. They need to be viewed with their armaments as appropriate to their displacement. "Most" AORs are in the 10 to 20,000 ton displacement range, and as such their armament is going to be appropriately lightweight, that is to say, not much. But then again, I never argued that these types of ships were going to be heavily armed. My original contention was that the 901 was lightly armed FOR ITS SIZE and compared them to the only other ships of the same type (AOEs), and by that comparison they are most definitely underarmed. But you insisted that smaller AORs be used in the comparison and then said "see, most of these ships are lightly armed". Well yes, they are, aren't they? But then again, they are also mostly, what, 3 to 4 times smaller than the 901? And almost all of the rest are about half the size of the 901. The one class that actually approaches the 901 in displacement, the 32,000t Fort Victoria class, is rather well protected with, as I said, 2 Phalanx and 2 20mm cannons.I don't think we can really count MANPADS as standard armament unless they are regularly mounted on fixed emplacements (which isn't the case in the Berlin class, I believe); and the 20/23k ton 903/A is armed with 4 autocannon mounts as well. The French Durance class has a 40mm Bofors and two 20mm Oelirkons.
The Deepak class are fairly well armed for their size, and the Fort Victoria class are decent as well.
But then there are ships like those which the JMSDF have, the Towada and Mashu class which to my knowledge are not regularly armed with any fixed weapons emplacements at all.
(All the above ships obviously can be armed with machine guns, but they're not fixed ship armaments in the way that we're talking about)
In the 901's case, if they are only equipped with 4 AK630s then I would consider that slightly on the low side, however I also strongly expect the forward platform to be equipped with a weapon as well; like a 76mm gun. If such additional armament exists then I think its armament would be quite consumerate with its displacement.
So I think it's quite reasonable to say that most AORs are relatively poorly equipped for self defence against aerial or missile threats; few are equipped with CIWS as standard, and most only have autocannons, and almost none have fixed CIWS SAM mounts like RAM of HHQ-10 equivalents.
So in the case of 901 class, an all gun armament even with "only AK630" as its primary CIWS, would not be too far from the expected norm.
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edit: the area of discussion for me was never really about the heft of mere "armament" on the 901 and other AORs/AOEs, but rather ciws capability, and I assume the subsequent discussion was talking about the relevant ciws armament of various replenishment ships. So I think a case can be made that quite a number of replenishment ships in many navies have relatively poor ciws capability, and 901 with "only" four AK630s (likely with an additional gun of some kind on the bow platform) won't really be diverging from the norm too much, its larger displacement notwithstanding. The most viable counter would be to say that the 28k ton Deepak class is armed with four AK630s as well which is the same CIWS armament as 901 class, but on average compared to the armament of other slightly smaller replenishment ships of other navies (many of which have autocannon armament, not CIWS armament), the 901's armament/tonnage is not too divergent from what we'd expect.