"Do not wish to digress here, but it does remind me a bit of James White’s charge/s leveled against Muslim apologists who quote 'liberal', critical Christian scholars in their debates, whilst James allows himself to use 'liberal' and critical Islamic scholars."
It’s less than clear why David Waltz finds this problematic. To begin with, if, in a debate with James White (or whoever), a Muslim quotes a “Christian” scholar who attacks the credibility of the Bible, then White is certainly entitled to point out that this scholar doesn’t speak for Christianity at large. At best, his views merely represent the views of other theological liberals. The Muslim can't use this appeal as an argument from authority.
And, of course, since White is a Christian rather than a Muslim, he’s not going to draw quite the same distinction with respect to Islamic scholarship. Since there’s a fundamental difference between a true religion and a false religion, scholarship attacking the credibility of a true religion (e.g. the Bible) is going to be false. It doesn’t follow that scholarship attacking the credibility of a false religion is going to be false, even when it hails from liberal critical scholars.
Apparently Waltz can only keep one idea in his head. He thinks it’s hypocritical if we don’t treat every religion equally. But equal treatment is only justified when dealing with equal claims. If two religions are fundamentally unequal (e.g. the one is true while the other is false), then, of course, they should be treated differently.