Using drugs is obviously bad for a person, but it is even worse when they hid and use dirty needles to do their drug. For this reason, needle exchanges are actually helpful to society. I believe needle exchanges should be legal because it may save someone from contracting a disease or getting sick.
If we want a bunch of dead IV drug users then we should stop giving out needles for free. If we want to continue the spread of AIDS and Hepatitis then we should stop the needle exchanges. Needle exchanges can help us register the sick junkies and find them the help they need.
While no one particularly likes the providing free drug paraphernalia to addicts, needle exchanges are actually a good thing. These people are going to use drugs whether we provide clean needles or not. And the cost of providing these needles is much less than the cost of treatment for the diseases that can be spread through IV drug use.
I know some people think that needle exchanges will help public health because users will have clean needles and will have no reason to contract diseases that comes from sharing needles. However, I think that the state should not be providing needles. We should offer incentives to get them off the streets instead.