It sucks, but isn't entirely unexpected. Pretty much every dev knows that the card payment processor companies have a reputation for being politically-motivated puritans, and it's kind of a miracle that itch.io escaped their notice for so long. We don't blame itch.io—even the bigger companies like Patreon and Steam are under a lot of pressure from the payment processors.
Our first release on Steam went well, and in theory, this shouldn't affect our current or future games, which are legal and on the less extreme side of things. The real concern is that when these game storefronts tighten their restrictions, they tend to not be very careful about enforcement, and even legal stuff gets swept up in their algorithms.