I found the question of whether he really doesn't understand the technical meaning of "back door" or is conscientiously trying to re-brand away from the negative connotations of the term particularly interesting. Maybe "side-door" would work?
It's so incredibly disingenuous. We're talking about a long established technical term with a precise meaning, but when world leaders are demanding it, they're uncomfortable using that term because it sounds like exactly what it is.
Saying it's "not a back door" is simply a lie, and I'm sure they or their advisors know it.