The original comments were made with Matthew Stafford sitting right by his side. It was intended (I believe) as a lob he could spike. And his answer came off as a dig of Goff. Why? Because Stafford was sitting right beside him. Had it been Raheem Morris, or Kevin Carberry, or practically anybody other than Stafford, it's a non-issue (with the exception of Austin Corbett....which could have been interpreted as a dig of Blythe).
Is McVay happy only because of Stafford? Does the fact DJax is now a Ram help? Tutu? Ernest Jones? Rochell? All those special teams guys they got in the draft? Resigning Floyd? Raheem Morris taking over for that other genius, Brandon Staley? Kevin Carberry replacing Kromer?
To me it was a combo of poor timing and not realizing his surroundings than the actual comment itself. And he's backtracking because he doesn't want to slight Goff. Of course, that horse has left the barn.