Bad at what? Typically when a compound is considered a "drug" it's - by definition - because it has an effect on the body/mind.

Like the old joke says: why do people use drugs? Because they work!

If I take an ibuprofen and it doesn't diminish my headache, then I'd consider it "bad". If I am nauseous or insomniac and take a capsule containing cannabinoids which settles my stomach or relaxes me to sleep, then I'd consider it "good".

What I imagine you're saying is that "ingesting drugs for some things is good, but ingesting them to relax, wake up, or otherwise feel differently than you currently do is bad".

I don't think anything in life is that simple.