Two wrongs don’t make a right. But two wrongs don’t necessarily make a wrong, either.
Just because someone makes a poor argument for their proposition does not mean that they are wrong. They may be wrong; they may be correct, but unconvincing. This is where the “Fallacy Fallacy” comes in.
Take a true statement like, “Eating lots of dark leafy greens is good for most people.”
The following statements are also facts:
Now, if I say, “You can never get too much of a good thing! Dr. Jones says we should be all be drinking a quart of kale juice daily, and eating raw kale at every meal. Eating kale is so healthy. It’s a good thing to put in a salad,” my fallacious arguments – that you can never get too much of a good thing and “because Dr. Jones said so” (our Dr. Jones being a quack with a YouTube channel who failed at being an OB/GYN), and because a quart of kale juice daily seems like an excessively high quantity – do not invalidate the fact that, in moderation, dark leafy greens – including kale and spinach – are generally a healthy thing to put in a salad. Maybe not for you, if hypothyroidism or kidney stones are a special concern, and probably not for most people in super high quantities, like a quart of kale juice every day, but they are usually a healthy diet choice in reasonable quantities, being high in vitamins A, C, K, and folate, minerals such as iron, and are high in fiber. They’ve also been shown to reduce the risk of cancer and heart disease.
Just because an argument is poorly made does not make the proposition untrue.