Yeah, but the weather is mild enough that I bet many don't fully realize the risk. In Helsinki, spending the winter sleeping outside is obviously not an option.
You'd be surprised what homeless in Poland pull to just sleep inside during harsher winter.
Forging keys, breaking and entering into garbage disposal or basements and of course trespassing and squatting are some of the things I've personally witnessed and that's not the end.
Yes, there are some facilities but apparently not enough and with conditions not acceptable to some of them.