That is a very ridiculously wrong statement.

> Despite being illegal they are still so very easy to access in almost all countries

You apparently have a pretty wide definition of "Very easy". I wouldn't have the faintest clue how to lay my hands on some heroin. Yes, I might start asking around in the vicinity of nightclubs based on hearsay that party drugs are supposedly sold there and the dealers might know someone who sells heroin. That would require navigating some scary situations quite outside my comfort zone. That's a completely different level of availability than alcohol, of which there are shelves full in every supermarket and ads plastered all over telling me how it will make me hip and attractive.

> Legalising them would bring users/abusers into a more public sphere where it is far easier to access harm reduction and the state can provide it without legal complications

You don't need legalization for that, merely decriminalization of use and possession.