While I definitely agree that her parents aren’t relevant at all, I think including that line does a lot for Rey’s self doubt, and that instead of her thinking that she was abandoned because her parents were assholes (which they still are), she can now believe that she was abandoned for a reason, because there is something evil inside her. Which is cemented in her head when she stabs kylo, causing her to go to the island. This also makes the Skywalker’s acceptance of her mean a little more. But it can also just be implied and her parents never mentioned.