Well I'm not saying I necessarily agree with it, but it begs the question of whether 'celebrating' (or, perhaps, simply not mourning) the death of some individuals is actually wrong? This would be different than encouraging/celebrating the murder itself.
I also think it bears consideration what 'public response' means here. Obviously I am just one person, but nobody I know (personally, or in the communities I'm in) has celebrated this in any capacity, let alone applauded the murderer. Are we basing public perception mostly on social media comments, which are a selective representation of public opinion at best, and blatantly fraudulent at worst?