I think that Cynog's letter is perfectly succinct and effectively damning of nothing more than a superficial campaigning technique. It ties in with comments titled Bletchley Park made (in Welsh) on his blog by Vaughan Roderick. He concludes that Kirsty Williams AM is saying in code that the Liberal Democrats are good at electioneering techniques but not so good at substance and principles. Sounds about right to me.
An elected representative has to talk to and support the constituency as well as taking those views to the forum where decisions affecting our day to day lives are taken. If that means being inside the 'bubble' for a while then so be it. But never forget where you came from and why you are there.