Those who object could clear up the litter, I suppose, instead of just complaining.
As I said in an earlier post, there is a tree near here which is redecorated with bunches of flowers at least annually. Yes, they wilt and start to look untidy, but what's a bit of untidiness compared with the anguish the young man's friends and family feel?
People who object can tidy up if they want.
And, in any case, they can be tolerant of other people's ways of expressing their feelings about something tragic instead of whingeing.