To elaborate, a lot of a legal case is determining how an actual situation should be matched to a law. An injunction essentially says: the court has good reaso

To elaborate, a lot of a legal case is determining how an actual situation should be matched to a law. An injunction essentially says: the court has good reason to presume they match in this way, ergo don't do X, Y, and Z while the case proceeds. If you then do X, Y, or Z, you have directly defied a court order, which is itself illegal. So the difference is between being able to construct a defense around "We didn't think what we were doing was illegal" (the original case) vs "We did that thing you told us was illegal while the case proceeds" (violating an injunction). Obviously, it's a lot harder to win a case on the latter.