What is strange about it? Fast should be clear. Responsive I'm guessing indicates they talked it over (related to fast probably). And reasonable I'm guessing means didn't threaten to sue him for hacking SO and accepted their mistake and wanted to fix it.
Its the expectation / perspective he had. He is talking like someone who had to report the problem, who had to have his issue resolved and was really pleased with the service.
Its not like he just bought an iPhone which had a flaw and he was happy with the customer service that resolved the issue, but it reads like that.
To be more blunt, he is using rhetoric in his article, probably acquired through osmosis from reading other articles, without actually realizing that the rhetoric doesn't apply to his situation.
As an aside, I find this phrase strange, given the context:
"The SO team was absolutely incredible to deal with during this. They were fast, responsive and reasonable."