The point is that if these airlines are profiteering from credit card charges, then they are flouting the law. If true, then it should certainly not go unchallenged.
Which have been pretty good at investigating these practices in the past, helping to reduce the problem of excessive payment fees. True, the cost will just move to the headline figure, but this is beneficial as it makes different airlines easier to compare. Those of us who frequent pprune may well versed in comparing airlines/prices etc. Your average punter (who perhaps only takes one flight a year for the family holiday) isn't always as knowledgeable.