Joseph:
The concern of OU, and many others, is that the Gay Rights groups will move to ban religious groups that don’t accept the doctrine of gay marriage, i.e. no tax exemption for shuls and yeshivos, not recognizing frum marriages, and perhaps banning members of those religions from public life and professional licenses. It is there position that opposition to homosexuality is similar to racism, and needs to be surpressed. You will note how in the Episcopal Church, the left wing groups are seizing churches from the congregations that built them. They are actively supporting persecution of anyone who doesn’t agree with them.
The OU is trying to make a point without being too provocative. In part since we are used to being a persecuted minority, there is no “hiddush”, but for Christians with no experience in being persecuted for their faith, this is a radically new environment they are facing.