Okay, while I'm expanding my vocabulary, any idea what a "valid" belief is?
For example, D.A.N. writes that standing up for your beliefs involves "understanding that other belief systems are valid, and no less valid than your belief system." We are also meant to understand that "beliefs do not always have [need?] concrete evidence to support them and that a lack of evidence does not necessarily make a belief system invalid."
Now what in the world does he mean? I would have thought that "valid" meant something like "good", "reasonable", or "justified" (i.e. epistemically permissible). But then D.A.N.'s claims would be plainly false. It's just not true that all belief systems are equally well grounded. You really shouldn't hold baseless beliefs. And it wouldn't make much sense to "stand up for your beliefs" if you didn't think they were objectively any better than the alternatives. Emotivists aside, opposing torture isn't like cheering for your local sports team.
In short: relativism is false. But are those who claim that 'all beliefs are equally valid' just silly relativists, claiming that all beliefs are equally good? A more charitable interpretation, I guess, would be to understand 'valid' in this context as meaning something more like 'tolerable'. All belief systems are equally tolerable. Some are stupid, perhaps, but that's no excuse for persecution.
But now we seem left with a truism. (Who seriously advocates a new Inquisition to forcibly root out false beliefs? Setting aside socially pernicious ones, at least...) There's not much point asserting something that no-one disagrees with anyway.
Perhaps it's simply a metaphorical call to refrain from expressing negative judgments. Some beliefs may be daft, but you shouldn't say so. It ain't nice. For that matter, you probably shouldn't even suggest that some beliefs are false. Believers might be offended. Now, it really wouldn't do to imply that people are ever less than perfect -- they might not like that, see. What? Something to be said for recognizing room for improvement? No, no, that clearly implies that we're not already perfect. That just won't do at all. Not at all. No.
*cough* Sorry, just had to get that out of my system.
To be fair, overly harsh scorn and derision might take the fun out of life. But if we value truth and rationality at all, there must be some legitimate place for reasoned criticism in the public sphere. If weaselly talk of "validity" is used to undermine these values, that's something to watch out for.