Does clutchless shifting REALLY not hurt a high performance engine?

[Kyle S]

I had a supermoto race bike, I constantly did not use the clutch when racing. I've read a handful or articles saying that it doesn't hurt the engine to shift without the clutch if you do it right.

I mastered how to do it, very smooth and very fast, but my bike's clutch springs and assembly are slipping horribly 5 months later. (I would race every weekend). I always used the clutch when taking off and downshifting, and when going from 1st to 2nd, just because of the stress on those two gears.

So does it really hurt it, even if done correctly?