As noted in this thread I’m not a Mac user, and we don’t know if this person ever got it to work
However I’d suggest (assuming you don’t have any sketches or data) trying to delete or rename these two directories (from the parts file format doc here
/Users/username/Documents/Fritzing/parts
and this hidden file
~/.config/Fritzing
as corruption in one or the other of these has been known to cause problems on Windows. Note as well the comments on delay while loading new parts from github (there is currently an update pending so that will be happening) although that doesn’t sound like your problem. I’d also delete and reinstall you distribution directory however you do that on the Mac at the same time as deleting or moving aside the two user directories (which a reinstall will not affect which is why you need to clear them). If you solve the problem please report back so we know what to tell others!
Peter