G.A. Cohen points out that Oxford-trained philosophers tend to believe in the analytic/synthetic distinction, whereas Harvard-trained philosophers tend not to. As an Oxfordian himself, he believes in the distinction. But he could have gone to Harvard instead, and so ended up a Quinean. Should this fact undermine his belief?
More detail is required. Here are two possibilities:
(1) The reasons upon which the Harvardians' beliefs rest are, impartially considered, no less weighty than the reasons behind the Oxfordian view. (The difference in their beliefs is merely explained by the fact that each side is more familiar with their own reasons.) If you think this is the situation, then this should immediately undermine your belief. It's [meta-]incoherent to believe that P whilst also believing that the weight of evidence fails to support P, since this is just to judge both [on the lower level] that P is true and [on the higher level] that P is probably not true after all.
(2) Alternatively, you might judge that, all things considered, the weight of reasons really does support the Oxfordian view here. So you're lucky you didn't go to Harvard, in much the same way that it's lucky you weren't born into a society of Flat Earthers (or a religious cult). If you'd been raised and trained differently, you would have been less sensitive to where the weight of reasons truly lies.
As a reflective agent, to truly believe something you must consider it to be epistemically superior to its negation. You must therefore hold that anyone who believes otherwise is ipso facto your epistemic inferior in this respect. (They are failing to believe what is best supported by reasons.)
Conversely: humility + metacoherence = agnosticism.
One might initially be tempted to retain one's convictions even whilst modestly admitting that others' views are equally well supported (all things considered). Cohen thinks this is a fairly common stance (e.g. between Protestant and Catholic friends). But you cannot coherently maintain this combination of first-order belief and higher-order humility. Which you should give up will of course depend on the details of the case.
For example, it seems plausible to me that a proper appreciation of religious pluralism should undermine common grounds for religious belief (e.g. 'religious experience' -- why think that yours is any more reliable than Akbar's?). But this is arguably just because there are independent grounds for skepticism, which actual pluralism makes more salient. The existence of geocentrist cults, by contrast, does nothing whatsoever to undermine heliocentrism.