Earlier quoted context omitted.
I'll take this opportunity to advocate for 'payment network neutrality' - given their importance in the economy, I agree payment processors should be required to process all lawful transactions, by law. We should require this of any national payments processor in the US at the federal level - or state, I'm looking at you, CA and NY.
Payment processors must not be arbiters of what is lawful.
There are numerous examples of companies doing something legal, that later blows up and they become the scapegoat for letting it happen.
As long as that happens, payment processors are going to protect themselves by avoiding certain industries.