Airbnb Intern - Hourly interview questions

Recruiter contacted me soon after I submitted my application online, saying I can set up a time to do a phone screen, the tech interviewer is so nice, when I was reading some reviews here I thought the interviewers are gonna be super scary and not gonna talk at all during the interview, but mine was not, he asked my about my thinking process, he gave me helpful hints and he provided me with rewarding feedback. I had a really really good time coding with him. Then HR told me since of the authorization stuff, my citizenship stuff, then they will not be able to continue my candidancy, It's a little bit sad because I stated my future requirement for work sponsorship in the original application but they still spent such a long time interviewing me until telling me I cannot move forward not because of my skills but because of something I cannot improve at all. However, I am glad they gave me this chance, other than this sad result I had a great time. (my recruiter is super super nice, she is super polite)