Earlier quoted context omitted.
Nitrous oxide is a popular inhalant. It's reasonably safe despite the usual hysterical claims, and it's unregulated in most countries, possibly because regulating it would drive users towards more harmful inhalants like glue and petrol.
It's not safe at all. In my country there are many people who have destroyed their brains using it. I would say even drugs like cocaine are safer.
It is wrong to claim it's an especially dangerous drug, particularly if your evidence is an anecdote about "many people who have destroyed their brains" in a nameless country based on no quantitative evidence and citing no personal experience.