You are making too many assumptions. Some squatters are the homeless, some are young-ish adherents of the far left, for whom this is a lifestyle choice.

The most famous Prague squat, Klinika in Žižkov, was full of blue-haired nepo babies whose parents were well connected politicians or businesspeople. That is also why it was tolerated for a fairly long time, and it was always able to summon a crowd of friendly journalists whenever someone tried to empty the building.

(Note that this is something that actual poor people rarely are able to - but lifestyle squatters who studied the same faculty before dropping out can do easily, as they still have the phone numbers of their graduated friends).

The common feature is freewheeling attitudes to drinking and drugs. Most homeless shelters or cheaper landlords won't tolerate too much consumption on the premises, or even have a dry policy. In a squat, anything goes.