[ben7799]

It's maybe rational if you're an Ayn Rand Objectivist and you think the older people you infect who die are not worth your time and energy to keep safe.

It's very much a selfish prioritization of the individual above everyone else to think you're under 30 so no precautions need to be taken even though someone under 30 is perfectly capable of passing it on to a whole bunch more people who might be older & vulnerable.