Don't mistake uncensored for unfiltered - Dave Chappelle probably writes and tells a joke a hundred times before you ever hear it, and it gets filtered through a LOT during that time.
Nice example since his recent stand up routine is getting a lot of flack for supposed anti-LGBT statements (I haven't seen it yet so I can't say if they have any value). With regards to the Pewdiepie case I am on his side here the quality of jokes doesn't matter it was pretty clear that they weren't meant to be taken seriously and that should be it.
He certainly does practice a lot. He still talks about bombing on stage in his newest standup. One of my favorite bits is how he talks about Michael Richards imploding on stage: https://www.youtube.com/watch?v=Kth0UOU5a_M