What I mean is that, in the case of divorce, obviously the Church vehemently disagrees with the legal definition of a divorce (e.g. the “dissolution” of a marriage). But it still takes advantages of it when it can do so in a licit manner (such as to help provide legal protection for a battered wife). This does not represent, by any means, an acknowledgement of a divorce, but the Church still allows for (and in abuse cases encourages) the usage of legal divorce in certain instances.
Similarly, while a same-sex civil union might be legally represented as an institution meant to be marriage-like, I could see, down the line when tempers weren’t as high, the Church using it in certain, rare cases for instances unintended by a civil union law, such as the necessary [legal and otherwise] caretaking of a same-sex best friend or what have you. Unfortunately, I find it highly doubtful they would do so with a same-sex “marriage” due to the much higher risk of scandal someone would be associated with. It’s one thing to say “we entered into a civil union so I could provide medical help to my friend who was paralyzed in a car accident;” it’s quite another to say “we got married so I could provide medical help to my friend who was paralyzed in a car accident.” The “we got married” part just sounds like capitulation by the Church, when in fact no capitulation would truly exist in either scenario. But the risk of scandal is too great with the legal term “marriage.”