It’s not that squatters aren’t considered to be trespassing. I’ve seen a number of news stories suggesting that owners can’t evict squatters - and in almost every case, it’s not clear that the owners ever tried to actually evict them and often not even clear that the people intentionally trespassed. For example, that Chicago news story says
Her attempts to evict the squatters didn’t go well.
but it doesn’t give any detail about these attempts , which I suspect means the attempts are limited to calling the police who aren’t going to be able to do anything if person has what appears to be a lease, appears to have been living there for some time and there aren’t any signs of a break-in. Even without a apparent lease, the police aren’t going to be able to do anything - otherwise, I could just call the police and have them remove my month-to-month tenant who has been living there for 3 years by claiming they are trespassing. That’s not something the police are going to decide on the spot , as they would be able to if there were signs of illegal entry. It’s actually possible that the “squatter” believes she has a lease, as it is not unheard of for scammers to “rent” or even “sell” property they don’t own. It doesn’t mention the owner actually going to court and losing the eviction case. The article about the house being sold actually says that the owner allowed her to move in three years ago and suggests he has never actually tried to evict her, as there is a mention that the family can’t afford to hire an attorney to work on an eviction.