JMHO, but I suspect it is because airlines make such a big issue about SNA noise procedures to their pilots that get those pilots overly agressive trying to fly "perfect" profile. I have seen checkairmen briefing new (to their aircraft) pilots for more than 30 minutes on just the takeoff procedure. It really isn't that difficult, just a little different.
Add to this the fact that AA's airport pages have very detailed descriptions of very specific flight profiles and procedures for each aircraft/runway combination to operate at SNA (I'm sure every airline has similar "warning" pages). These, combined with a reminder message on all flight plans to/from SNA about its cerfew and noise monitor locations places undue stress on pilots not familiar with the airport and its procedures. Same goes for landings.
Had a captain once brief me for 15 minutes on not "floating" the landing because of the short runway. When he was done I asked him if the runway was as short as an aircraft carrier (823 traps), then greased the landing and exited the runway at taxiway-E (short of full length) using idle reverse and minimal brakes. He never briefed me again -- and did all SNA landings the rest of the month.