This is one theory, and it's a theory that's hotly contested. Asserting it as a fact doesn't actually make it one, and we're currently watching several large scale experiments testing if decriminalization helps society. Early results are not promising.
But that doesn't mean it's not needed, because it is. Violent drug addicts are locked up in other countries too, and if you spend time hanging around in public high on meth then at the very least police are going to tell you off.
We do need to reduce the prison population, but by the time someone has reached the point of heavy drug use and street violence the odds of rehabilitation are very low. No other country has a good record of rehabilitating those people. So, the only reasonable way to reduce the problem is further upstream with better opportunities and support systems for youths.
All I see is a claim that harsher drug laws would not have helped this victim.
Also rudeness, but being rude is not victim blaming.
Edit: Pretty please someone explain? Am I missing some obvious implication?
From here it looks like people hate the grandparent comment so much that even incorrect criticism will get treated as true. Which is really bad for a discussion website. I hope I'm wrong about that, but I'm failing to find another way to read things.