why are publicly traded companies special? The speculation is not on securities.

You're not participating in a "market" (even though they call it that), you're purely gambling and speculating. People have been doing this since currency was a thing. Even gambling laws don't apply in my opinion. If I told you the government will publish evidence of aliens existing tomorrow, and we make a bet on it, that's not really gambling, it's not so much a game of choice as it is a competition of who can predict things better. The other person might have insider knowledge, but it's up to you to either take on that risk or assume despite that your knowledge about the topic will overcome their potential insider knowledge.