"Illegal drugs increase crime, partly because some users turn to crime to pay for their habits "
If all drugs would be illegal, then they would be mostly so cheap that this argument falls apart very quickly. Drugs are only expensive because they are illegal. Poppy and coca are not hard to grow and neither is hemp. And the chemical drugs are way more cheap to produce. So very high quality stuff would remain expensive, the same way a fine wine is expensive, but just to get drunk is cheap (even with taxes).
"and partly because some users are stimulated by certain drugs to act more violently."
And yes, that is true, but one of the most famous and widespread drug that makes people aggressive is already legal - alcohol.
"Legalization, however, will not affect addiction"
And this is up for debate, for some it will be easier to get help, because the stigma and criminalisation is gone, but yes, some might start it, because it becomes avaiable. And I did not look in the recent numbers, but back then when I did - in the netherlands for example, drug use decreased, after marijuhana was legalised. It is quite complex - some people are afraid of anything illegal, some are appealed by it, mainly teenagers who are in most danger of becoming addicts/developing brain damage.
"better treatment, education, and research are needed to curb dependency on drugs and the adverse health and social effects of drug use."
But this is true. And better, than jail people who simply need help.