I don't think this is quite what's happening here. Overall USCIS is funded by fees, but operates a system in which some kinds of applicants subsidize other kinds of applicants. So, applications for asylum are free to make even though they cost USCIS a lot to adjudicate. To make up for this, USCIS charges extra for applications in other categories, like employment-based visas.

I'm not sure what exactly is happening in this case, but by saying "Because the US can’t seem to get a handle on its borders" the article author seems to be claiming that artist visa fees are subsidizing asylum claim applications.