I read the rule a little differently and it makes sense in my mind. By description it probably implies that within the stat block. So if the MM shows the base creature as wearing armor, then the skeleton should be proficient in it as its base monster is obviously proficient. If its base monster isnt wearing any, then your skeleton (who is based off of the base) shouldnt be capable either.
And with this logic, i would think if you were to animate a skeleton, and the original was proficient in armor, your skeleton should still be proficient in armor, even if the monster manual says it normally isnt. Only makes sense, and doesnt bend or break any rule out there.
(Yeah i know, sense doesnt really belong in the rules, but sometimes it helps with clarifying what they probably meant)
And with this logic, i would think if you were to animate a skeleton, and the original was proficient in armor, your skeleton should still be proficient in armor, even if the monster manual says it normally isnt. Only makes sense, and doesnt bend or break any rule out there.
(Yeah i know, sense doesnt really belong in the rules, but sometimes it helps with clarifying what they probably meant)