First of all, rudeness among the general public is common. Perhaps OP has never worked in a customer service position, but in general, it is my experience that politeness does not really happen. Second, when people are on vacation they are under stress and in a different environment and likely facing problems that they are not accustomed to dealing. They also are dealing with workers who in general are more interested in efficiency instead of politeness, eg: ticket takers, TSA, cabbies, etc. However, the norm is that a hospitality host is polite to strangers, welcoming and friendly. It is actually the definition of hospitable. In short, you are being paid to take other people's crap and be accommodating to them. If rudeness bothers you, probably hosting or any other customer service type job is not for you.
How I cope with it is that is that I put in my listing that my expectation is that I will most likely not have personal contact with guests, but if they need it they have my phone number and I live three blocks away from my AirBnB unit. I also provide resources for guests to utilize if they have problems. I say pretty much that if you want personal service, the hotel located in my building costs three times my rates, but if you just want a place to sleep and hangout to live like a local, you can save a bundle by staying at my AirBnB.
As for the WiFi. The problem you are going to have is unmet expectations. AirBnB does not force you to provide WiFi and you can disclose that you do not provide it. But that still does not change the fact that guests expect it. You have the same problem as the hosts that choose not to provide bedding. Perhaps the easiest solution would be to provide WiFi and include the cost in your rental rate. If you absolutely do not want to provide it. The next best thing would be to provide instructions in your house manual about how guests can get WiFi in your town, with phone numbers and addresses of providers. You could also add that many Smart Phones are capable of being a WiFi hotspot in case guests are unaware. That way guests who want WiFi at least know where to start to get it.
If you wanted to help guests you could buy a WiFi Hotspot such as this one: https://www.walmart.com/ip/Straight-Talk-Unimax-U240C-3G-WIFI-Mobile-Hotspot/30824075 Lend it to guests unactivated and make them activate it with Straight Talk over the phone and of course deactivate it when they are done. You could also see if your local Walmart carries them to refer guests (mine does not stock them)