rear derailleur. That's what he means.

The 'ghetto' SS is just stripping off th front/rear derailluers, shifters, etc, choosing the best chainring/cog selection for chain line and shortening the chain.

the downside is that some cassettes/chainrings basically give you two SS options. REALLY HARD or really easy. otherwise the chain will try and jump to an adjacent gear mid ride and give you all sorts of trouble.