"Who cares?" While you may not OutThere, quite obviously from all this discussion, many do.  Symbols matter- imagine  our emotions when we think of the cross, our flag,  the swastika or a Nike swoosh.   Interesting places in interesting cities have names that resonate with local color from Ellis Island to Harvard Yard to North Beach.  
Ken Kesey was a brilliant author but no angel, as his excessive drug use indicates.  He is, however, one of our best known citizens ever, and a rare combination of writer, hippy and Webfoot.  In any case, great creative personalities  often seem to have had problems, quite often with alcohol. We're all a balance of the good and  the bad, as we saw when we weighed Mathew Deady's many accomplishments against his leadership in favor of slavery.
Anyway, Kesey's statue shows him reading to his grandkids, not dropping acid.  Plus, we have a nice balance down the street at the library with Eugene Skinner who certainly  never did drugs nor wrote a famous book.