All brokerages of any size and scale, as well as all consumer-facing companies have poachers like this on the web. We've dealt with this for years at Real Living. It's impossible to register all of the different typos (although the one you uncovered for Zillow seems obvious for them to grab).
I agree that it's a smarmy consumer-decieving, feeding practice and it's far too common in the real estate space. As consumers become ever-more educated, they'll spot the fakes immediately.
This is way interesting I would never have thought of it myself. I guess I'm too naive, too new, too innocent or too stupid to catch on to these things.