Sadly, you are all too correct on this. The Constitution today is simply whatever the Supreme Court says it is.
So from an original intent point of view it would seem that Rehnquist non preferential support of religion in general would be eminently constitutional.
Of course times have changed and since Lemon truly is a dead letter with Alito joining the court we are left with O'Connors neutrality doctrine. So the obvious question to proponents of a neutrality doctrine is this. How is neutrality achieved by ncluding the secular and rejecting anything religious? And how is neutrality achieved by making the religious dependent on the secualr?
Establishment clause jurisprudence is a mess. It needs spring cleaning.