"Bad writing" is bad writing.

By which I mean, if your critique of something is "bad writing," you don't know how to write criticism. You don't really know why you don't like it, and you definitely don't know your feelings well enough to make an argument worth someone else's time.

This isn't to invalidate your feelings. I'm the champion of "the stuff you don't know how to say yet is also worthy of respect," on record, on god. But this is where we get to the line between personal opinion and critical thinking, a line that "having a take online" simplifies away - critique is also an art form, the awkward daughter of a classic literature course and a mathematical proof, and it is possible to make poor art that doesn't achieve what you want to achieve. Calling something out for having "bad writing" is a sign that your call-out is bad art.