Your parent's comment makes no sense.
Water can kill you, too! It does not mean that drinking water is bad.
But not all potheads are lazy, and many non-potheads are.
Media tropes sure are great at propagating myths and generating false stigma, which creates a chilling effect for ever correcting the former.
Having lived in a country where cannabis has been legal for about a decade now it's quaint seeing this kind of casual disrespect levelled by a stranger.
I wonder if this kind of mindset is still common here and people just don't vocalize it anymore, or if it's the kind of mentality that continued criminalization perpetuates.
It's actually not even just HN. I've noticed this with many people in real life (US).
It's especially strong with the subset of Boomers who never used it. They make it part of their personality to have not used it, while often fully embracing alcohol and ignoring all of the personal and societal risks it brings. Surely they pass this mentality onto their kids with a 50% success rate.
Maybe it's some kind of inferiority/superiority compensation mechanism for not being a hippy like their rival sibling was, etc.
There was a deliberate effort to demonize weed in the US as it's associated with mexicans, black people, and counterculture, and it's difficult to monetize if it's legal (anyone can just grow it).
https://www.youtube.com/watch?v=Uy_lCjA6poo
Also, there are alternatives to smoking it: use a dry herb vaporizer with no tobacco and you avoid the vast majority of the negative health effects.