OK, so you don't have much history with him, just the past year. Maybe the year before, he helped everyone earn much more than the benchmarks. Every adviser has good years and bad years.
Still, 2% under benchmarks is not really a huge underperformance, so I would have expected him to give you some kind of rationale to put it in perspective.
Unwillingness to even discuss it indicates that he did in fact see your email as combative (and I'm sure you didn't intend it that way).
Overall, put it behind you and get on with your life. The alternative could have been to go on paying his fees for years for results you could easily achieve on your own. That would have been worse.
Still, 2% under benchmarks is not really a huge underperformance, so I would have expected him to give you some kind of rationale to put it in perspective.
Unwillingness to even discuss it indicates that he did in fact see your email as combative (and I'm sure you didn't intend it that way).
Overall, put it behind you and get on with your life. The alternative could have been to go on paying his fees for years for results you could easily achieve on your own. That would have been worse.