Strictly speaking this isn't a conventional free speech issue since the government isn't involved here, just private businesses. That said, there's a de facto

Strictly speaking this isn't a conventional free speech issue since the government isn't involved here, just private businesses. That said, there's a de facto duopoly on payment processing that gives these companies near government-level power to dictate terms. Realistic alternatives don't exist and would be insanely hard to start.