|laziness, impatience, and hubris|
If the Perl5 defaults are so error prone, then why on earth didn't you work to change them in the perl core...
I'd really like to say more, but I really shouldn't have to.
they will be enforced by others that don't have any clue about perl - our PHBs and project managers.
In the absence of PBP, clueless managers wielding arbitrary rules with little technical knowledge would wield arbitrary rules with little technical knowledge. That's the thing about justifying stupid rules--they don't need good reasons. They'll do it anyway.
Meanwhile, capable people have one more tool and one more book to read to gain more knowledge--knowledge that some of us learned the hard way.
I'm fairly bad with power tools. I'm also fairly glad that the people who came before me put safety guides on bandsaws. Yes, I know they don't prevent all accidents, but I have all of my fingers and toes today because the people who knew using power tools better than I did not only taught me how to use them well but helped put rules and guides in place in the hopes of preventing me from misusing them.
I fail to see how that's a bad thing, or how people determined to do the wrong thing no matter the cost or justification make the existence of those rules and guides bad either.