After checking with support, it appears that as of VBAI 2015 f2 there's no ability to delete multiple VBAI state diagrams at once. I have an inspection with multiple states, and would like to modularize/strip off a small subset of the states to import to another inspection. I can delete one at a time, but would be useful to do this easily.
This makes sense. I will add this to our backlog of features to consider for the next release.
Thanks!