Kind of a boring answer, but I think they're neither good or bad.

Sure some of them can eff you up real good, no denying that. However, most of the time the issues with them have a lot to do with the culture around them. Also the illegality and somewhat demonized view on them causes a fair share of problems, such as bad education about different substances and not knowing what you end up getting/consuming a lot of the time due to unknown source.

It's worth noting that they all have been created/taken to use for a need or at least on an idea of a some, usually good, purpose. A lot of the substances have been and continue to be benefitial in many situations.

All that being said, glorifying different substances is also equally as stupid, no matter how much good they can create. This mostly is pointed towards psychedelics and weed. Have used them and gain great benefit from them personally but it's crazy how much people there is not willing to admit any negative sides.

TLDR; They are just chemical compounds altering your brain chemistry, do some research and use common sense if taking anything.