If you change registrar-level things about your domain, they're now required to confirm your contact info with you. This isn't a "DDoS", or "deadly", or any of that nonsense: it's a new strategy to ensure whois data stays updated.
Whether or not it's an effective strategy for keeping whois data accurate is another debate (I don't think it is), but talking about it like some malicious act is pointless.
I read about this originally when they made the rule and it seemed arcane and ridiculous, I dont know how it ever was passed. I believe everyone who some experience with whois info knows the information is either false or hidden behind privacy emails and contact information. If they are not, they are subject to annoying or even abusive misuse. (I remember someone back in the day calling me repeatedly because they found my website after I beat them in some video game, the internet is filled with nutters.)
If ICANN wants to know the details, I dont care, but if all the internet wants my phone number, they can take a long walk off of a short pier.
That's bad.
The registrar is public information. The registrant's contact information is public (or at least publicly accessible). So, wait a year for people to get accustomed to clicking on links in emails from their registrar, pick a target domain, forge an email from the registrar, send it to owner contact with a link to a phishing page. Congratulations, enjoy your new domain.