Blackcatter, It's called Argumentum ad Hominem. Discredit the man and you discredit his argument. It's a common enough ploy and you really shouldn't be surprised to find it used on you.
It saves the accuser the drudgery of actually having to think about refuting any points you may have made.
It's so much easier to dismiss you as an ignorant nitwit who doesn't read the right newspapers or whatever.

troll