I'm not sure I really believe the argument.
Stuff like this used to happen to celebrities and ordinary people, the only difference now is:
- there isn't a studio system that tries to suppress this stuff
- people actually display this as news
- people will pay for this news.
Heath Ledger's party tape was supressed by hollywood. No one has done the same for these other matters.
Who to blame? These stars, their parents, and their managers (not agents). These are the people who should be concerned with morals and ethics.