“ However, lack of control over what went on in the park caused a multitude of problems. Drug dealers and users arrived from all over Europe, and crime became rampant as dealers fought for control and addicts (who numbered up to 1,000 ) stole to support their habit. The once-beautiful gardens had degraded into a mess of mud and used needles, and the emergency services were overwhelmed with the number of overdoses, which were almost nightly. Platzspitz, or Needle Park as it was then known, became a source of embarrassment to the Zurich municipal council and in 1992, police moved in to clear up the park.[clarification needed] The drug scene then moved to the adjacent area of Letten railway station, which closed services in 1989. This spot was also cleared by police in 1995.

Today Platzspitz has been cleaned up and restored, and is presented by the authorities as a peaceful, family-friendly garden.”

https://en.wikipedia.org/wiki/Platzspitz_park?wprov=sfti1#

So hands off was a total failure, so they gave up and forcibly removed people.