I'm sorry, but what? Since when is knowing how to or being able or even wanting to do something a pre-requisite for criticizing something? What ever gave you that impression? That's not how anything works. You can say something is shit even if you don't know how to make something.
Have you never said a movie sucks? Or a TV series? A game, a book, a song, anything? Do you think those things are easy to make and that's why you were allowed to say they sucked? According to your "logic", if I give you an apple pie that turns out to have a big pile of turds inside, and you complain about it tasting like shit, I can just reply "oh, well, you make your own apple pie then, you seem to think this is super easy work." Surely you see how stupid this is, right?