I've also removed the "ref($proto) || $proto" cargo-culting from your code. If you want people to be able to call your constructor as an object method as well as a class method then you should probably have another (object method) constructor called "clone" or "copy". It's generally considered bad practice to have one constructor that is used as both.

That paragraph is neeedlessly insulting, especially to someone who is manifestly new to Perl OO, if not OO in general. Further, it offers no pointers to more information on why "ref($proto) || $proto" is a bad thing, and makes an overly broad claim that it is. Without intending to divert this conversation down that path, I'll note that the question is not as settled as one would presume from the claim.