Honestly I'd blame Namecheap, not ICANN. My registrar was much more relaxed - I did not need to take any action
Please take a moment to view the WHOIS listing for each of the domain names you currently have registered through us. Please verify your mailing address, email address, and the administrative and technical contacts assigned to each domain name are correct. If your WHOIS information has changed or is inaccurate please log into your account manager and update accordingly. If your WHOIS information is correct, you do not need to take any action.
This is a bit different, and it's possible your registrar is not yet using the latest RAA (Registrar Accreditation Agreement). Specifically, the email you're talking about is the once-a-year verification email that all compliant registrars must send. The OP was dealing with a new rule which is part of the RAA 2013, which adds the requirement for verifying emails within 15 days of any registrant change that impacts either the name or the email address of the registrant.
Please take a moment to view the WHOIS listing for each of the domain names you currently have registered through us. Please verify your mailing address, email address, and the administrative and technical contacts assigned to each domain name are correct. If your WHOIS information has changed or is inaccurate please log into your account manager and update accordingly. If your WHOIS information is correct, you do not need to take any action.