i totally agree with you with respect to the obams, but have you never heard the phrase used before? because that would affect how one perceives his use of it.
As I said, taking all things in total, my perception of his use of this phrase is as I stated. Not any kind of deliberate “code”, just another gaffe, another remark that alludes to things that are part of him.
I have never heard this phrase spoken about in the context of political disagreement. I’ve heard “worked me like a dog” in reference to physical labor. I have never heard someone say “they talk about me like a dog” when referring to others who disagree with or don’t like them.