The biggest issue here is not insider trading itself, but the fact that (foreign) policy is being used for insider trading.
Think of the tariff madness of last year. The biggest issue wasn't that insider billionaires were robbing outsider billionaires. The bigger issue was the massive stress small businesses had to endure, who didn't know how they were going to survive.
I am of the mind that legalization of this practice would decrease trust in the marketplace to an extent that I think is necessary at this point. Of course, the better alternative would be to actually enforce these laws and increase confidence in the marketplace but how will the inside track billionaires make their money if we do?