Actually, she is being literally correct: "... at the behest of the constituencies they serve ..." sets it all out.  The constituency they are elected to serve is the governing party.  Any belief that that description somehow attaches them to the public at large is sheer fantasy.
There is a dying need for the Constitutional Court to, once and for all, clear up the mess of two contradictory parts of the constitution: the first declares that the MPs are representatives of the public, the second is that they serve on behalf of, and at the discretion of, the party that nominated them.