Emma B: You wrote:

"'when the music started to turn political this lady and her friend got up' - quote from the original post

How this this metamorphosize into the perjorative
'those two old birds'? "

Well, your position seems to be very much in the minority among those posted here, but that should not impact its potential relevance. Since I'm the person whose choice of words you question, I feel constrained to answer.

As I read the phrase "as soon as the music started to turn political," it is clear that the two women interrupted the show and walked up to Sol while the performers were singing. That alone would seem to earn them a perjorative reference.

And, as far as my phraseology "those two old birds" is concerned, I think that it is only very mildly perjorative. Believe me, I could have written a lot worse, and almost did! (My first draft featured a different word beginning with "b.")