The argument that I see isn't that it's easy to hit on a quarterback with an early pick. It isn't. The draft is a lottery for every position and homeruns can go to the wrong team and become nothing, while others can go to the perfect spot and become Aaron Rodgers. The odds are low, but tell me what the odds are if you don't even try. Grooming a late round quarterback is nice, and should be a recurrent theme every few years, but that's Plan B.
Carson Palmer (2003, 1st overall)
Andy Dalton (2011, 2nd rd)
Cam Newton (2011, 1st overall)
Aaron Rodgers (2005 1st,#24)
Ben Roethlisberger (2004, 1st, #11)
Derek Carr (2014, 2nd, #36)
Philip Rivers (2004, 1st rd, #4)
Drew Brees (2001, 2nd, #32)
Russell Wilson (2012, 3rd, #75)
Matt Ryan (2008, 1st, #3)
Eli Manning (2004, 1st overall)
Peyton Manning (1998, 1st overall)
Joe Flacco (2008, 1st, #18)
Teddy Bridgewater (2014, 1st, #32)
Alex Smith (2005, 1st overall)
Matt Stafford (2009, 1st overall)
For all of the misses in other lists denoting how dangerous it is to take a shot at early quarterbacks, this list says you need to take a swing in the first couple rounds - almost exclusively the first. It sucks to strike out, but I don't know of any homeruns made with your bat on your shoulder.