Up to the third comma, yes, but all the rest seems to go beyond that pretty arbitrarily.

When they say anything that “may damage the goodwill of the corporation”, and qualify that with “in the sole discretion of the Corporation” that just means “anything we don’t want to be associated with, and we will be the judge of that”.

That’s what makes it so vague, how is a Merchant or an Acquirer supposed to know what Mastercard might find damaging to the goodwill? They have to guess, or use trial and error*. Most will just err on the side of caution, which means customers get blocked from even more purchases, just to be safe.

* Or talk to Mastercard, which Valve apparently tried, but they wouldn’t respond.