"option -r not recognized" when running xattr -r

It’s hard for anyone to help if you don’t give details, but I can only guess …..

The man page describes -r starting

If a file argument is a directory …

So, did you specify a directory?

What's the full command you are using or what are you trying to do?

Are you using the standard xattr command that's built into macOS? IIRC there's another program out there by the same name with completely different syntax. Try running type xattr; it should say something like "xattr is /usr/bin/xattr" if you're using the standard one.