it appears to me that you're misunderstanding those cases.

in texas gulf sulfur, the defendants were officers at the company. they were directors at texas gulf sulfur and they were trading on texas gulf sulfur stock. they have a fiduciary duty to the company that a stranger doesn't have.

that's what the judge in carpenter is referring to. if you acquire the info by virtual of a fiduciary relationship, you aren't free to trade on that info. in texas gulf sulfur, they had the fiduciary relationship to the company because they were officers at that company. not so here.