I tried using the SoapUI Uninstaller and then reinstalling. Still getting the same issue. I noticed when I opened SoapUI again after reinstalling that it loaded the same project I had open when I uninstalled. Are there additional folders/files I can try deleting along with uninstall that will guarantee a clean uninstall? It's clear there are still some settings/files that persist.
Update: ok I've noticed that if I get rid of the default-soapui-workspace.xml, and soapui-settings.xml sitting in my Users\<username> folder, I get a clear workspace and I see all of the Assertions in the Property Content category. However, I still cannot get into any other categories such as "SLA."