@Shelley369 I don't know what you mean by "Airbnb is supporting the host". Airbnb doesn't get involved in whether a review is true or not. How could they know which party is telling the truth? They don't remove negative reviews written by guests either, even if the host says the guest is lying.
As far as them writing this for racist reasons, it may be true, but you have no proof of that.
Was the host lying about the furniture being moved around and not put back, too?
I'm sorry this happened to you and have no idea why the host would have said you left it a mess if you didn't. Most hosts just expect guests to wash the dishes, bag up the garbage and take it out to the bin, i.e. clean up your personal messes, and leave the place reasonably clean and tidy. Guests aren't normally expected to clean the bathroom, vacuum, etc, unless they've made a big mess (like kids dropping food all over) and making the beds is pointless, as the bedding is going to be changed anyway.
Have you messaged the host about this?