Only with 'New Light' could baptisms be annulled (maybe supported by no recorded minor baptisms in Bible). After all, marriage is (supposed to be) for life - and is a 'contract' between adults - but there are Biblical reasons why that contract can be dissolved.
The problem is, if those Baptised as minors (as I'm sure many of us here were) were annulled, then it would be easier to discuss issues with family/friends still in. So not viable to the WT. Loss of control.