I don't know if any of those who constantly root for extreme hot weather have really experienced that...I am sure they have not. It's not just the number od "deaths" that matters, that's just a part of the story.
For personal reasons I have lived for many years in a country where the weather, during summer, it's exactly what you "dream of" (high humidity, no rain for months, max temperatures constantly above 35°) and believe me it's a nightmare in terms of quality of life.
You can't breathe properly, you sweat even if you don't move, there is nothing you can do (other than staying indoors or napping) during most of the day and you have a constant feeling of feeling tired and headachy. Not to mention the toll that a weather like that takes on the environment (everything is brown and dusty, wildfires, water shortages etc.) .
It's really beyond me how you can root for that kind of weather when here in the UK we have the best summers of the Western world (and hence the most beautiful landscape).
Really and with all due respect but you don't know what you are talking about.