Whether or not this is true seems rather besides the point. If you're looking at Hitchens as an academic, then 'winning' debates through being bombastic and condescending does not to further your own position or general discourse, so is not really 'winning' at all. If you're looking at Hitchens as an entertainer, on the other hand, then sure, ridiculing others rather than arguing points might mean that such a style achieves something; entertainment value. But that certainly does a disservice to what I think Hitchens was trying to achieve.
As a disclaimer, I'm not familiar enough with Hitchens to say definitively what his style did achieve, but from how you've described it, apparently not much, or at least not much more than a dry religious/political satirist possibly can achieve.