Capgemini Engineering interview questions

The HR called me to reach there at 11 a.m..After reaching there I had to wait half an hour and after that they called all the candidates for 1st round.In this round they gather all the candidates and asked them question about their background,about their birth place.Basically they checked for voice and accent.After that they told us to wait outside for next round.We all were waiting outside,but no one call called any of us.Then after 2 hour,one of our candidate asked them about next round to the HR,She again told him to wait outside,they would call.After waiting again 2 hours,I asked them about next round then she told all of us to leave for that day.It was really bad experience.They could immediately tell us to leave if we were rejected.Why do they took too much time to reply?