I mean despite your terrible sarcasm, we do have rational regulations on things like alcohol or gambling because we recognize that it helps protect people overall, sometimes indeed from themselves.

Your argument is essentially 'I don't drive drunk, therefore we don't need any laws against drunk driving' since the expectation is that people will behave rationally. Or that we don't need regulations against things like cigarettes because people know the harm already.

Obviously there's room to debate on how socially dangerous something is and whether it warrents regulation; hence the ongoing debate on marijuana legalization; but in general he's right: relying on anecdotal evidence and extrapolating that is bad form. It provides context and reason for your arguments, but is not an argument in itself.