Liberals have, over the past several generations, come to dominate all the mainstream self-defined Christian denominations; and all these churches have declined.
Furthermore the most liberal parts of these denominations have declined the fastest. Indeed, quite often the most conservative minority parts of churches have been growing, while themajority liberalest parts are declining.
In a very obvious, in-your-face, kind of way; it would seem that there is at least a plausible case that liberalism has been bad for Christian churches, and has perhaps been substantially (although not wholly) responsible for killing them.
Liberals might at least entertain this hypothesis; or they might even acknowledge its truth but claim that liberalisation was necessary anyway; or they might admit that liberalization had caused short-term decline, but that in the long-term it would lead to a revival... but no.
Liberal Christians have never - so far as I have seen - ever even acknowledged that there was a very straightforward and potentially significant correlation between liberalization and decline.
For example, the advocates of the ordination of women to the priesthood, or as bishops, never seriously consider the strongly-evidenced hypothesis that such change will, on the basis of considerable experience, almost certainly lead to the swift and massive decline of that denomination?
(Somebody must have said something of the sort somewhere, of course; but I have never seen this hypothesis even discussed in hundreds of thousands of words advocating liberalization either of specific denominations or Christianity in general.)
Why is this? Is it sheer ignorance of the correlations? Maybe, but if so, that ignorance would have to be wilful - therefore not true ignorance.
Or is it just plain dishonesty? Do they actually know that liberalism is killing their mainstream churches - but choose to deny the fact because they want the liberalism to continue?
Yes, I think so; that's it.
And this would then mean that liberal Christians, who now dominate all mainstream churches, objectively value liberalism more than their churches - an interpretation which seems to be consistent with all the facts.
Note added: I think the key to thinking about this is honesty. We need to ask whether it really is possible nowadays to be an honest liberal Christian (except for the brand new and utterly un-experienced convert). I don't think it is - especially not in terms of the relationship between liberalism and the churches. It's not as if liberalism is anything new in Christianity, there are several generations of experience.
This fact of lying about the institutional consequences of liberalism would not necessarily of itself mean that liberal Christians also valued liberalism above Christianity itself - only that they valued liberalism more than their churches.
But of course they do also value liberalism above Christianity, and this is shown by the fact that liberal Christians always redefine Christianity to fit with modern Left Wing ideology, to a greater or lesser extent; and never the other way around.