Inhaled nitrous oxide is NOT the same chemical at all. Alkly nitrites are formed as a liquid and the vapors are what is inhaled. These are two entirely separate things.

You are wrong, hypoxia is easily avoidable even when using pure nitrous oxide with no added oxygen, just don't continuously inhale an uninterrupted stream of it or use it in an unventilated area, fucking duh. It takes a prohibitively massive dose at once to actually die of asphyxiation, or months of consistent heavy use to achieve long-term nerve damage from oxygen deprivation, which is why actual cases of either are extremely rare compared to rates of recreational usage.