@Trent93 I see this host has 5 listings, so they are more of a property manager than a hands-on host, and those are the types of listings that one reads the most guest complaints about.
Also, none of the properties they manage have particularly high ratings, and while most of their reviews are quite positive, some do mention issues. So you can't claim you weren't warned.
And when you arrive to find a place unacceptable in some way, Airbnb protocol is that you are supposed to first contact the host, to give them an opportunity to correct the issues. It's possible that the cleaner was scheduled to show up that morninng, and unbeknowst to the host, didn't, and would have been mortified that you arrived to find it that way and sent someone over to clean right away, and offered you the first night free, or paid for you to go have a meal somewhere while the cleaning was done.
And if the cleaner neglected to show up, the previous guests could have left the door wide open when they left- happens all the time, and I can assure you no host would be okay with that and certainly wouldn't be happy to know the place was left unsecured.
So quite honestly , if it was just dirty, that's something the host may have been responsible for, but that the door had been left open makes it sound like this was all some situation the host wasn't even aware of.
You have to give hosts a chance to make things right, not just assume they are terrible hosts who don't care about their properties or their guests.