you assume you know everybody's financial situation,,right? Things change for people and often it's unforeseen. A declining economy, a medical emergency, a loss of a job,etc,,, can contribute to financial instability. For you to be annoyed or say suck it up is a ignorant thing to say. I know a guy who owns 6 rental properties and all run on propane. We have bookings and when propane more than doubles in a few days it is disaster. Fuel prices, garbage disposal, snow removal and food has all risen and now propane doubles. The problem with your thinking is that it is narrow. i understand your point and you are correct for a narrow margin of people but for many here in the UP where the household income is way below city folk, this spike will hurt. I encourage you to look at it in a more broader sense and than you may see what many experience.
Many people use propane as a secondary heat source and use smaller amounts and do not want to have a butt load of money sitting in a tank when they have a lower income to begin with. For us to get a contract we have to be on a "keep full" program. Getting over the hump of filling the tank can be difficult especially when you have a 1000 gallon tank and can dump in 850 gallons costing over 2 grand. As prices of everything increase it does make it harder to own secondary properties but to say we shouldn't own them is pushing it.
Being concerned or complaining about propane more than doubling in price is reasonable. i am glad you are fortunate enough for it to not be a problem but don't fool your self because most my adult life I was fortunate enough to do anything I wanted and didn't worry about this sort of thing but life changes and I hope you don't experience hardship.