Personally, the mostly-rare occurrence of people making love in public is not my concern. Your concern over this seems like muddled thinking. Are you objecting to the presence/existence or damage to your sensibilities of exhibitionists?
For example, take the incidence of drivers speeding in neighborhood streets or on the highway. that morality and safety issue is a far bigger risk to the public at-large. Where's you concern and/or outrage over that?
I'm far more concerned about the immorality of wars, killing, robbing, child abuse, trafficking/slavery and other crimes and immoralities against humanity.
Where's your outrage about that? You're creating a tempest in a teapot.