The confusion is between "the assembly clang generates is the obviously correct assembly for this operation" (true) and "the obviously correct behaviour for a compiler is to generate the assembly that clang does" (disputable, as while the assembly GCC generates is less clear, there may be advantages to doing it that way in e.g. performance). "Clang does the obvious, correct thing." is ambiguous between these two meanings.
I disagree with "ambiguous", you sneakily changed "obvious" to "obviously" in the second sentence.
obvious, correct != obviously correct
Sounds like by "obvious" the parent means that Clang uses the most trivial approach.