@Jorge1656
While I can see why this really irks you (especially the guest book entry), personally I am not sure if you should post a response to the review as it seems you don't often respond, so it will only make this one stand out more, rather than be buried under more recent ones as time goes on.
If you do decide to respond, keep it calm and as neutral as possible. I wouldn't mention discrimination as, unlike in the guest book, there is nothing in the review that reveals this.
I do know how you feel though. I once had a guest leave a review that made my neighbourhood sound like the scariest place she'd ever been to, even though nothing bad happened to her at all. I don't know if the fact that it's a very multi-cultural neighbourhood influenced her perception of it, but I am guessing that could be the case. She said that there were many 'dodgy' looking types around. It seems like no one approached her or bothered her in any way, she just decided that these people looked 'dodgy' and advised other guests to walk quickly with their heads down.
I thought this was utterly stupid and was very tempted to respond but, after I cooled off a bit, decided it was not worth my time.