As for the applicability of those rights to specific issues, that's up to the courts, which have a record of creative interpretations to do whatever they want to.
> But buying stock means you don’t own it (otherwise you wouldn’t need to buy it)
That doesn't even make any sense.
I've spent the vast majority of my professional career working in finance, subject to SEC rules and regulations regarding insider trading. None of this precludes own, buying or selling stocks. SEC rules prohibit acting upon material nonpublic information for financial gain, the likes of which congress critters do all the time. It is this act of buying and selling on material nonpublic information that is illegal for the common folk, and ought to be illegal for those making the laws that affect the stocks. Don't want to be subject to mandatory holding periods and disclosures? Buy ETFs like the rest of us. And yes, insider trading rules apply to my family as well. I cannot tell my parents or children or siblings or in-laws or friends any material nonpublic information with the intention of financial gain through buying or selling stocks.
If one is going to engage in buying & selling of stock to which one is privy to insider knowledge, there are means to both buy and sell said stock. It usually involves disclosures of intention to buy or sell and a predetermined date. It may typically only be done within a certain time frame, typically quarterly after earnings have been announced. If you're buying, there's typically minimum holding periods (length varies, but it effectively precludes day trading). Point is, there are legal ways to buy and sell within the rules. No one is being deprived of rights. But, if you buy or sell in violation of the rules, there may be forfeiture involved, because you were never allowed to make the transaction in the first place. Break the rules, be prepared to pay the penalty.
Congress is not above the law, and they should be subject to the same rules and regulations as everyone else. This isn't a Republic or Democrat issue. It's common sense, but doesn't benefit the people in charge of making the laws, so it doesn't happen. Or if anything does happen, it's loudly and publicly championed and then quiet neutralized when things have calmed down and no one's looking anymore.
Let me put it bluntly. If I, not being a member of Congress, pulled the same thing Pelosi does with her husband and their trading, my spouse and I would both be in jail and rightfully so. And no, Pelosi is by far the only one, but she's a very public example of this as the Speaker of the House.
Now, if it were legalized, professional investors would be monitoring the trading activity of insiders. down to the microsecond. Any adverse trades by insiders would provoke an immediate reaction, and so the gains by such trades would be minimized.
Furthermore, such moves would be public information. Would you invest in a company where the insiders were making adverse trades? I wouldn't.
As for Congressmen, if I was trying to unseat one, you bet I'd make a campaign issue out of them if they're using the seat for personal gain.