Generally stealing cars is clear-cut and easy to prosecute. The opposite is true for insider trading. As a result, things that look an awful lot like insider trading occur all the time without any interest from the SEC.
I'm not very equipped to judge legally what is or is not a crime, but it does seem like there's a lot of leeway for people in control of public companies to effectively take money from their investors.
Yes but it's important that the "crime" of "insider trading" exist so that investors might imagine that executive aren't doing that every single day. Also it's important that the crime is totally discretionary so that prosecutors can punish every single non-executive who somehow gets wind of non-public information while never bothering executives who donate to the right PACs.
I'm not very equipped to judge legally what is or is not a crime, but it does seem like there's a lot of leeway for people in control of public companies to effectively take money from their investors.