Be fair! He didn't surrender; he simply didn't engage.
- He started with opinion and dogma:
I disagree with the contention that requirements always change. I see it as a euphemism used to excuse laziness in gathering requirements.
- And when I responded with challenge and irrefutable evidence.
- He knee-jerked & prevaricated
- When that was met with a spoon feeding
- He responded (typically for his ilk) by attacking the format rather than the content of the message.
- And when that opinion was further met with authoritative refutation...
- He attempted assassination by condescension
At no point did he offer evidence in support of his opinion; but he didn't so much surrender, as simply 'shut up'; which was probably wise.