The bad thing here is that irrespective of Mrs k_getchell's right to enter the lounge this sort of language and behaviour is unacceptable. Imagine someone considering moving to BAEC and "giving the lounge a try" and being rebuffed in this way. BA would instantly lose a potential customer.
That Mrs k_getchell did have the right to enter and was given such rude short shrift is incredible. I just wish I had been behind her in the queue to enter the lounge. I would would have offered some pretty severe advice to the offensive dragon, including asking her to apologise.