FireEye Systems Engineer (Pre Sales) interview questions

Went through the entire interview process (4 rounds) and at the end of the process, I was told that the role is being offered to an internal candidate. If this was already decided then why even take the effort to interview external candidates and fill them with hopes and towards the end, apologize as if nothing happened. This is truly frustrating. The company should seriously improve their hiring process so that this doesn’t happen to other candidates.