Update: passive aggressive owners too! Lovely.
I'm a barista who has been working at indie shops for a long time and I work at one now: I don't think my review was "trashing" in any regard, and it seems odd to me to receive such a defensive response when I simply stated that I felt we didn't have a good experience and gave a real and concrete reason why. It's not trying to be different, honestly, it comes across as unwelcoming to someone who might want to sit awhile and continue to spend money at your business.
I was honest, and I don't think it's out of line to give an honest review on a platform specifically designed for doing so, especially since two people behind us also didn't notice your oh-so-clearly marked sign. Maybe a sign by the cash would be easier to spot?