Well, yeah, obviously lol.
I don't mind being *outside* in 20c for a little while, but being inside is the real shitshow. Our buildings are specifically designed and insulated to keep as much heat in as possible - heat does *not* escape from our apartment buildings and houses at all, and we don't have air conditioning. And that's not even talking about the humidity we often experience in the north, especially for people like me that live in coastal cities. There are way more factors than just "hahAA ppl in finland r so pale and white xddd" that people don't consider.
I am 100% sure I could handle 30c, and maybe even higher, if I had air conditioning and a house that was designed to dissipate heat effectively instead of turning your building into a makeshift oven.