Why do defensive players go at 3pt shooters?

[Woodsa]

I understand the under control close out to make the shoot pause. But I do not understand the jumping up and trying to block it only to repeatedly running into them.

I don't have access or the time to review a few games to see hiw remotely effective vs. hurtful this technique is?

The amount of times Purdue has influenced, impacted, or blocked a shot vs being called for a foul has got to be low.