Part one is ad hominem, and has no relation to the validity of the argument.
As for part 2, the point is not that the world is certainly an illusion but that we don't know either way. Given that, meta-doubts are implied.
For me personally, my posistion is that rationally there is no way out of skepticism but that I believe it false on religious style faith.
I've raised arguments for philosophical scepticism before, which have mostly been argued against in a Popper-esque manner of arguing that even if we don't know anything with certainty, we can have legitimate knowledge on probabilities.
The problem with this, however, is how you answer a sceptic about the notion of probability having a correlation with reality. Probability depends upon axioms of probability- how are said axioms to be justified? It can't be by definition, or it has no correlation to reality.