I always thought the paranoia was caused by the illegal status of the drug and the possibility of being caught and punished for using it.
My main objection to legalization (as opposed to decriminalization) is that when the users have toked themselves into befuddled unemployability it will be declared a disease and they will go on the dole. Then you and I have to pay to keep them housed, fed and high.
we live in a society where the government has to protect us and we don’t suffer the consequences of our behavior. In an ideal society your would have freedom to do that and if you lose your job, the government and taxpayers wouldn’t pay. The flip side of the coin of freedom is individual responsibility
There's no reason to think that people who were responsible enough to avoid marijuana when it was illegal, will after legalization be so irresponsible as to toke themselves into befuddled unemployability.