Google Pre Sales Engineer interview questions

I attended rigorous Google Hangout interview with three people and asked to attend an in person technical interview. I had to give an architecture and a demo. But, the problem is that if the solution is not exactly with all the components they believe the correct one is, you are rejected as technically not qualified. Instead they should have probed me why I believe the solution(s) - I had to put two alternates- are optimal and looked to my thinking process. They don’t give any mercy and I felt like they don’t even respect the fact that a problem can be solved with multiple different technologies. Also, they don’t give any mercy when the demo failed due to their WiFi issues during technical interview. BTW, I passed all other aspects of the interview. I thought technical interviews are to measure candidates potential and not to match with their own perceived correct answers. After all candidates spend a lot of time to build the solution and learning the technology. At least recognize that fact. Honestly, I would not spend any more cycles with them They were all nice during the interview though and paid all expenses.