Slap the backboard T?

[cozzmokramer]

Here's the play.... offensive player is heading to shoot a layup. Trail defender goes to block shot and just misses touching the ball (in fact he may have actually grazed it). His momentum causes him to slap the backboard while the ball is above or on the rim. The shot falls out and misses.

What is the call here?

The referee called it a Technical foul, but I'm not sure that's right. I thought if it was an attempt to block the shot it wasn't a technical. The rule I found says it's a technical if:

ART. 4 . . . Illegally contact the backboard/ring by:
a. Placing a hand on the backboard or ring to gain an advantage.
b. Intentionally slapping or striking the backboard or causing the ring to vibrate while a try or tap is in flight or is touching the backboard or is in the basket or in the cylinder above the basket.

It seems to me that the word 'intentionally' refers to every part of art 4, b. So this should not have been a technical because it was not intentional. Am I interpreting this correct?