If someone takes your bad advice it's on them right... not on you?

depends how bad the advice is and the context in which it was given. for an extreme cast, it's obviously bad on me if my (fictional) dimensia-addled grandma runs out of toothpaste and i advise her to use bleach instead, that's obviously bad on me. if some random person asks me for stock advice and i tell them to buy double down gold, i won't feel quite so bad if they lose money.

It is their fault, many times it is good to play devil's advocate, so that they themselves realize how silly they have been.