Is there anything inherently wrong with publishing in a bad journal?
It probably won't hurt, but this is the sort of thing you should discuss with your adviser.  Since the journal doesn't have fees, it is unlikely that it is an outright predatory journal but that doesn't mean it is worth responding to. Is this in a field where responses are a normal thing? Other relevant questions: And what do the other papers in the journal look like? Are they absolutely awful or are they just mediocre? That should tell you something about how worthwhile it would be to respond.