Forescout Technologies interview questions

After an initial phone call, I had a first interview with the QA manager and the Frontend Lead. The next stage consisted in doing a test at home for checking my qa test automation skills. The difficulty was ok, the length of the test was too much, in my opinion. After doing good at the test, I went there again for a final interview with the same 2 people. I also passed that, so the next day I got a call from the HR department and they made a verbal offer. The most important part though was the fact that they assured me that this is just a formality, but I would need to wait a few weeks until they get the approval from the CEO. After one month, they call again and tell me that they won't hire me anymore because the CEO rejected me. Why? Because they have a rule about not hiring people who had more than 3 jobs for the past 10 years. Now, i don't have a problem with them having such a rule, in the end it's their business, even if I don't think it makes any sense, but they knew about this rule from the start and did not tell me. More than that, they assured me that the job will be mine (if I accept, of course), so I did not look for another job during that month of waiting for them, even though my previous contract already ended. Therefore, now I have to start looking for a job again and I also risk losing my 30% ruling because of taking this break. All in all, the interview process was ok, but considering the way this ended, I consider it an unprofessional experience.