I think that the reason why most people choose to mind their own business isn't because they aren't concerned.
This is well documented phenomenon and is called "public ignorance". TL:DR the larger the community the more pronounced it is and it is based on the fact people tend to think that somebody else will take action.
It's good you called the cops, if he means no harm there is nothing wrong if cops ask him a question or two he wants socializing anyways:). If he will be there the next day, give another call and they will have to take action since all your calls are documented and registered i am sure.
Yep, and there is also the "if I can't be singled out as having not taken action" issue. The cops didn't even do a drive by, but I am sure if it was me sitting there for 9 hours of the day and no one knew me, they would have. My wife spoke to him last night, without knowing he had sat there all day and said that he was strange, but still didn't want to call - after finding out how long he was there yesterday and that he is back today. Finland is a safe country in general, but Finns hold a false sense of security.