It is impossible to be a "progressive" Christian. St. Paul very clearly denounced homosexuality among other forms of sexual decadence in the age of the Roman Empire, and our age is not fundamentally different. LGBTP ideology is incompatible with a Christian sexual ethos, and choosing to embrace such an identity is choosing to rebel against God. As you cannot be a progressive in good standing without embracing LGBTP, there is no room for serving two masters here. All "Christians" purporting to affirm LGBTP ultimately just wind up saying "God is wrong, I'm right." There are no scriptural arguments in favor of it, there is no tradition defending it, and claiming that "times change" is simply self-delusion.