I'm actually not getting anything to appear using your code in a QueueTopic report but I can get category names by the GUI on the QueueTopic report and because of that I might also be misunderstanding the question but when I generate an issue report, the GUI also allows for showing the QueueTopic category name exposed to text mode as:
displayname=
linkedname=queueTopic
namekey=view.relatedcolumn
namekeyargkey.0=queueTopic
namekeyargkey.1=category.name
tile.name=component.objectcategories
valuefield=queueTopic:objectcategoriesNamesString
valueformat=HTML
viewalias=queueTopic:category.name
One nifty thing I've learned from Melinda for collections is this:
listmethod=nested(project.projectUsers).lists
so supposing that, maybe you can apply it to queuetopic.objectCategories?