Insider trading is just one more thing that increases income inequality. Not surprised that the Supreme Court passed on this. A little off topic but I am so pissed off that US Congress members have passed laws that make themselves and their assistants immune to being prosecuted for insider trading. You know the system is getting more corrupt when such bad behavior is not even hidden from public view.
The reason it wasn't illegal for them before the recent law was because they weren't insiders. Congressmen do not owe a fiduciary duty to third party companies. And they don't owe congress or the government confidentially for stuff they learn on the job.
In fact the whole insider trading rules were not even passed by congress. It's a mix of SEC regulation and essentially federal common law that created insider trading law.
Also congress wasn't really immune. If a congressman payed Tim Cook for Apple info, that would have been illegal.