[Disclaiming necessary for texts in the public domain?]

Thank you for the answers, I understand now

[Disclaiming necessary for texts in the public domain?]

I hope I'm in the right place here. I tried searching for the specific issue, but couldn't find a clear answer.

I got a "Disclaimer warning" review, telling me that in my Story "What Men Call Love" in the "Harry Potter - Het" section (username "lordhellebore"), I had to put a disclaimer for a poem from the 1800s that is in the public domain now. I'm just wondering if there have to be disclaimers for texts in the public domain?

Thank you.