One factor is the ongoing campaigns from number of moral crusading groups who lobby them to cut off payment processing for things they don't approve of. NCOSE has been working for decades on the project, and targeting credit card companies has been a successful tactic for them for a decade or so.
[1] https://www.eff.org/deeplinks/2020/12/visa-and-mastercard-ar...
[2] https://www.newsweek.com/why-visa-mastercard-being-blamed-on...
[3] https://scholarworks.iu.edu/dspace/bitstreams/761eb6c3-9377-...