That's not what they said. Whether your condition is diagnosed or not, it's your responsibility to take care of it. If you're chronically late, you should set timers or write notes or whatever helps—whether you've got class-A ADHD and take meds or just assume there's something wrong with your sense of time.

Just saying "I'm time blind, sorry not sorry, deal with it" is not an appropriate reaction to causing trouble to your surroundings.