During the really hot spells we had this year our butter melted at least partially when not kept in the fridge. The rest of the year we can keep butter out of the fridge. If it was consistently 5-10 degrees hotter that just wouldn't be an option really, at a minimum we'd need a cold pantry. I can see solid butter being way more effort to keep than it is worth.
Oh sure, but melting isn't spoiling. It'll melt here sometimes too, but harden back up overnight (or in the fridge) and it's fine.
I thought we were talking about it actually spoiling, going off, growing mould or whatever. If anything ghee is worse in terms of melting isn't it? Here in the UK it's typically liquid (sold in cans) at room temperature, and will only solidify in the fridge. (As a separate point that's sort of interesting taken together with its higher smoke point than butter that hasn't been clarified. To a non-chemist such as me anyway.)
Your butter is probably modern factory made kind, which is pasteurized. It can last much longer than "natural" butters of old.
Same applies to milk. My parents used to boil milk up until 20 years ago, mostly because they grew up in households with cows and they boiled milk to kill bacteria. It took me years of showing them the label "Does not need to be boiled" to get them to drop the habit.
What is a normal indoor temperature there? In summer most have their AC keep the house below 27 here. We are a fan of 22 in my house but that is considered a bit wasteful. In winter we try to keep it above 18 unless it gets really cold. This last winter it got down to 8 inside.
I'd say most people probably have their heating set to 21 to 22, which for most of the year is more than the external temperature (hence why so few houses here have AC).
It's not the first time I'm hearing this at all, so I'm not saying you're wrong, I just don't understand.