That happens when much of citizenry can be characterized as “rich blokes who will take coke at some point with no shadow of doubt”. When everyone involved knows that, including the voters, it’s an easy decision.

However, in many other countries the general population mostly forms their opinion on drugs, weapons and even political freedoms based on fear of what will happen.

They don’t look at all this critically, thus don’t understand that the worst things happening because of the current state of things they don’t know anything about, because information is not and will never be as available as their thought process requires.

That involves said current state of things funding things like cartels, criminal groups in governments involved in drug trade (it’s much more profitable when you ban all the competition), creating a vector of control over addicted people. These all have ugly consequences - violence abroad, strong (and rich) mafia groups in governments.

The correct thought process would be comparing abstract mechanisms. In abstract no consumable substance should be illegal, provided the buyer knows its contents and effects.

BTW, in abstract the right policy about weapons ownership would be opt out, not opt in, - mandatory mental examination of every adult citizen, but also mandatory weapons ownership for those who pass it! Perhaps except felons. With other exceptions being a process involving some justification being filed - as in pacifist views, religious reasons, bad atmosphere in family thus inability to keep it secure, something like that. It’s not about “good guy with a gun”, it’s about distributing real power. People who should own weapons are not the same people who want to own weapons generally. Thus mandatory.