> We're also seeing corporations removing discounts for NRA members. I don't see a link between that and legal fiduciary duty in those actions. They seem to be reactions to social pressure.

Thats a slightly different, but related [0] effect. The NRAs own PR approach has made special deals with the NRA a PR liability for many businesses. Public relations aren't something companies burn money on for entertainment value, they do it because corporate image impacts the bottom line, because it has a direct effect on things like consumer choices and ability to attract and retain talent.

[0] related in that lawsuits are also used to address political issues (and targeting tangentially-involved businesses formgun violence is a well-known example of that), so that the public mood on gun policy that shapes the reaction to NRA PR efforts also is a factor in the legal risk that firms face with Section 230 being weakened.