Even if you didn't clean your coop out for a fortnight or maybe even a month, you still wouldn't get sick. Nor would your birds. Thats not to say you should leave it that long lol, but I noticed your layout is open air on dry soil. Bacteria does not thrive at all in those conditions, unlike the musty, damp, cramped humid closed barns where a thousand commercial birds are kept amongst the dead & dying.
There is absolutely no way anybody could compare that with a small backyard flock kept in far healthier conditions. Why are you worrying about dust? You coop has excellent ventilation, any chicken dust will just float away.
I would not worry at all about such scare - mongering, just keep conditions dry & well ventilated & you probably will find your birds are much healthier for it.