Welllll, as to RAI, it appears you are correct.
This Sage Advice includes a link to the Player’s Handbook errata and answers some D&D rules questions.
dnd.wizards.com
However, I greatly disagree that the wording of the spell leaves no room for misinterpretation. As evidence, I submit the words of the many people who have expressed their confusion here and elsewhere; it is abundantly clear that it is possible to misinterpret it. And it seems to me there are two good reasons that people might misinterpret the spell. First, the phrase "regardless of what kind of armor it is wearing" calls attention specifically to armor and will cause (some) people to think that armor is particularly germane to the effect of the spell. In your interpretation (and Crawford's intent) armor is just one factor among many. As I noted previously, that intent would be much better expressed by "regardless of what its AC would be otherwise", or, in fact, by simply leaving off any such phrase entirely. "the target's AC can't be less than 16" is more concise and less subject to misinterpretation.
Just to be clear, I agree that the phrase "regardless of what kind of armor it is wearing"
is logically consistent with the intended interpretation. But that does not mean that that is the only interpretation with which it is consistent (it's not), nor that that is the interpretation that everyone will consider the most likely (it's not), though some may.