Isn't rental income taxable, which is presumably why those other things are deductible? Same elsewhere although people to whinge about.
I live in London, and I can tell you that it can get much worse. I suspect it's more about the overseas investors than anything else, who buy knowing that the prices will go up and the returns are good enough that they don't even bother renting them out. Councils around here are reacting by considering laws that will allow them to forcibly use all the empty homes to help ease the housing issue, or by introducing special taxes for non-domiciled owners.