That page strongly supports my case.  First, it doesn't contain any actual way to determine what disruption is, meaning that the definition is left to be decided elsewhere (like on the Ref Desk Policy Page).  They then warn that "...it is tempting every now and then to use the word to refer to certain acts that, while they should not have been committed, do not actually disrupt anything, either. Please try to avoid this."  I believe this applies to your characterization of LC's actions.  They certainly were no more severe than "small-scale vandalism": "For instance, one user gratuitously insulting another user, while inappropriate, is not disruptive.  Neither is simple small-scale vandalism."  They then follow up with an example quite similar to what happened with your block of LC:  "Furthermore, don't cause actual disruption in an effort to fix a perceived disruption. An excellent example of this is the Great Userbox War of 2006; several users who claimed userboxes were disruptive, set about deleting and trying to stop further creation of such userboxes. The ensuing fight was orders of magnitude more disruptive than any supposed disruption for which the userbox opponents were able to provide evidence. Just because you don't like something doesn't mean it is disruption. Disruption is a large-scale hindrance of Wikipedia's ability to function, whether technically, administratively, or socially. An insult, or even a string of insults targeted at several users, does not do this."  They then finish up with: "Please note, however, that 'disruption' is often Wiki-code for 'something admins don't agree with', which also seems to be exactly what is happening here.