The simple fact is this Toyota dealer and JPI are INDEPENDENT BUSINESSES like jrag said. They can choose what they want to work on and don't. A Lexus dealer wouldn't change the oil in a Honda Accord so why would JPI? He's selected a concentration for his business, Toyota and Lexus vehicles. If he accepts ONE Honda then not only does he run the risk of his techs, being trained in Toyota and Lexus doing something wrong but then he has to worry about working on this guy's Honda in the future, including any referrals. All of a sudden he doesn't have a Toyota/Lexus service shop anymore does he? Who knows why the dealership chooses not to work on Lexuses, maybe they've found the owners are more difficult etc. BUT thats life and you have to respect their decision. Nobody HAS to do anything for you. Just because they own a shop doesn't mean they're compelled to change your oil.
I detail cars for clients on the side, 2-3 a month probably. I don't accept anything thats not a luxury car because thats what I want to work on and what is usually in the better condition, and I only agree to do a car when I've personally examined it. Its made some people a little irritated that have wanted me to detail their 1990 Chevy Corsica, but its my business and my decision.