Both of those answers are valid and will remain valid even if the links go dead, all someone has to do is go looking based on the information provided.

They are absolutely answers and should not have been flagged NAA.

You could have gone looking and found an online version of the hier(7) man page and you could have edited it into the Accepted answe it's about 12k characters so it would fit.

The FSH and LSB though are too big to edit onto the 30K character limit set by SE so really the only option the OP had was to mention them by name and then leave helpful links.

What's the problem here ?

Both of those answers are valid and will remain valid even if the links go dead, all someone has to do is go looking based on the information provided.

They are absolutely answers and should not have been flagged NAA.

There are lost of things you could have done with out flagging ...

You could have gone looking and found an online version of the hier(7) man page and you could have edited it into the accepted answer it's about 12k characters so it would fit.

The FSH and LSB though are too big to edit onto the 30K character limit set by SE so really the only option the OP had was to mention them by name and then leave helpful links. You could have done nothing in that case.

I just checked elsewhere and whilst there is an option for a Very Low Quality on Questions, the same does not exist for Answers.

I guess, if you felt the answers were low quality you should have either edited them (if possible) to fix them up, downvoted and/or left a comment.