The reply is that way because the OP didn't seem to acknowledge that using unique_ptr in this case has serious problems. He still insists on using unique_ptr, reasoning boiling down to "you should avoid writing code because you may create bugs". As if slowness or lurking crash caused by not writing code were not a bug in itself.
Oh I know, using unique_ptr to implement linked list is a terrible idea. Having an element be owned by its predecessor is a very weird idea, not to mention that it wouldn't work at all for a doubly linked list.... I'm just saying that your comment could have been written in a nicer way.