This article was clearly tongue-in-cheek, and playing the victim doesn't help anything, I'm afraid. There's nothing wrong with being able to laugh at ourselves and at others.
My English mates call me a sheepshagger. Should we be "offended" by that? One of my English PC-loving mates even asked me why I'm not offended: he thinks I ought to be. There's an entire grievance industry out there with an army of people wanting to be offended by anything and everything trivial, don't join their ranks.
There are far more important things in life to worry about, than a few paragraphs having a lighthearted poke at us sheepshag- uhh I mean Welsh.