Flock Office Manager & Executive Assistant interview questions

Call with internal recruiter - extensive grilling but friendly. Video call with Head of People - asked me to go through my CV and asked me how I found out or was recruited for each role which I found unusual. Never heard back from them after two interviews and a follow up email which I find disrespectful of my time and the whole application process. How hard is it to send a thanks but no thanks email? What does it say about a company that is happy to ghost potential employees?