At the end of the day it’s a code of ethics, you’re not dealing with a company, but an individual and if they’ve put their name to something and decided to go back on that, the consequence of not being seen as trustworthy and being called out for it is supposed to reduce the odds of going back on your word. Ideally you’re also meant to care 
Without full details you should be able to access the site regardless of a valid certificate by hitting advanced and then accessing it anyway. If it’s complaining about HSTS you can bypass that (at your own caution with this - 'Clear or Disable HSTS for Chrome, Firefox and Internet Explorer' ). Note that it’s in place for a reason and without knowing the situation you probably want to be using a disposable browser or a VM in case a site is compromised.