Synack interview questions

I applied online, a recruiter reached out and we had a really nice chat. I then met with the hiring manager who was also very nice. He did give me a weird assignment at the end to reach out to the person who currently does the job. The current employee didn't respond to my first email. I had to follow up with him, as the hiring manager told me I had to connect with him before moving on to the next round. He then didn't respond to my second email, which had questions. It was a pointless assignment and a waste of time. The last round of interviews was four 30-minute interviews in one day, starting at 6:30AM and going until 11:30. I never said I was available at 6:30 and felt it was inappropriate to schedule an interview at that time. So did the person I was interviewing with. He was in another time zone but commented how it was too early for an interview. One of the four was 10 minutes late to the interview, and one of them clearly didn't read my resume and kept asking questions about jobs I never had. Everyone was very nice, but a few more red flags popped up. After the last round, I emailed the two recruiters I spoke with, the hiring manager and all four people I met with in the last round. None of the seven responded to me. It was clear at that point they weren't moving forward with me. A third recruiter sent me a generic "we're not hiring you" email. To his credit, when I asked for feedback, he did respond, though it was another generic response. Totally fine if I'm not the right candidate, but a little respect would have been appreciated. Overall a negative experience, which is disappointing considering how much they champion their culture. Scheduling an interview at 6:30AM, having none of the seven people I talked with respond and one interview being very late is just a bad way to handle hiring.