If we ignore that they asked him programming questions not relevant to his position, there's the whole "they didn't even know they interviewed me, so they called me again to ask me the same exact things" FAIL, plus the lie about "we'll call you in 6 months".
Are you joking? Did you even read their post. The guy literally called and asked the same set of questions twice, then didn't follow through with what they said they would do.
I cannot believe you're even asking "how could this have been a more stellar experience for you?" the gall.
Interviewer 1 called OP and asked questions. Then it was lunch time and he forgot to put result in the CMS.
So the same guy popped up a week later to Interviewer 2. He was reading off the same script, so of course his questions are the same. Not his fault, or Google's per say - Interviewer 1 happened to forget a step. (Which is sad, but we all make mistakes!)
The way it was phrased implied that it was the same person (would have otherwise been "I had been asked these questions before")
Job interviews are a business transaction (after all you are there because you want their money). Not hiring you is fair game and once they have decided/committed to pass on the opportunity it wouldn't be rational to waste money by continuing a pointless discussion.