What do you think would've happened if Delly consistently went over the pick and Tristan didn't switch/go underneath to stay in front of Curry?
He's not helping him get over the pick, he's helping Delly by taking the decision of whether to go under (leaving Curry an open 3), or go over (leaving Curry a wide open lane to the rim) out of his hands. Delly more often than not didn't have to think about what option to take, because he knew, if he did his part, Tristan and the others would cover the rest.
Delly didn't make him go 0-8. It was joint effort from the Cavs.
Let's review said game where Curry went 5-23:
Curry's first miss - Shumpert over the pick, with Tristan hedging hard forcing him to jack up a 3-pt shot late in the shot clock.
Curry's second miss - Tristan guarding him solo; Warriors role players not getting free - again, forcing him to jack up a jumper late in the shot clock
Curry's third miss -
He actually loses Delly on this play (Delly caught behind pick from Draymond) but misses a wide open floater in the lane
Curry's fourth miss -
Again, he loses Delly on this play (Delly caught behind pick from Ezeli - Mozgov doesn't hedge), but misses a wide open 3-pt shot
Curry's fifth miss -
And AGAIN, he loses Delly on this play (runs around a screen and Delly isn't aware - Mozgov and Jones force him into a tough reverse layup)
Curry's sixth miss -
Curry runs into corner and forces a step-back three - first occasion where Delly is actually guarding a miss shot
Curry's seventh miss -
With three seconds left on the shot clock, Curry is forced to take a 3-pt shot against Delly with Jones hedging
Curry's eighth miss - Tristan is guarding him with the help of Shumpert and Curry is forced to take a shot just before the halftime buzzer
Curry's ninth miss - Curry with a transition 3 and Mozgov's extended arm is enough to put Curry off
Curry's 10th miss -
Delly slips over and Curry gets the ball on a wide open 3-pt shot but misses
Curry's 11th miss - Thompson guarding Curry solo and he forces up a contested 3-pt shot
Curry's 12th miss - JR Smith switches onto Curry after Delly is caught behind a pick and he forces up a contested jumper
Curry's 13th miss - Curry forces up a contested 3 against LeBron as the Warriors are down by five with nearly a minute to go
Curry's 14th miss - Curry forced up another contested 3 against LeBron and Shumpert
Curry's 15th miss -
Curry pump fakes Delly on a 3-pt attempt, Delly does well to recover but Curry forces another 3-pt shot
Curry's 16th miss - LeBron forces Curry into a tough layup in transition
Curry's 17th miss -
Shumpert and Delly force Curry into a tough jumper with a few seconds left on the game clock - where the Warriors are by one point.
Video of all his missed shots -
NBA.com/Stats
As you can see Delly only contested Curry's missed shots on three plays (which can be attributed mostly to him) - not this 0-8. This is why it's important to provide context with those stats, because they often give the miss to the closest defender in the vicinity and not if they actually guarded the shot.
No they're not. Clearly you don't know how it works.