Yes. Advice should be evaluated on it’s own merit. Arguing that a person’s condition or habits invalidates their argument is known as a red herring fallacy. The goal is to distract from the argument rather than address it. If a personal trainer tells you to eat twinkies all day, that’s still bad advice. And yes, your out of shape fat father telling you to eat fruits and vegetables is still good advice too.
The take-away here is to focus on the validity of the argument and to avoid all types of distractions. It’s natural to question consistency. However, this concern doesn’t address the science behind their claims. This is why red herrings are so effective. And why thinking well is so hard and nearly impossible to do well all the time.
Take the following short debate:
Mike: “We need to reduce carbon emissions to mitigate climate change.”
Fred: “But you still drive a gas-powered car, so why should we listen to you?”
While Fred’s concern about Mike’s personal choices might be valid, his counterargument is not. Mike could still be right or wrong about climate science, but Fred’s argument doesn’t address that. Fred has yet to make a valid counterargument. Logical fallacies are one of the Four Mind Traps covered in the TST Framework.
In this case, hypocrisy might exist, but it’s not relevant to the debate. Think about doctors who advise patients to quit smoking while they themselves smoke. Their hypocrisy isn’t on trial—smoking’s harmful effects are.