Does the fallacy "if they are wrong then the other side must be right" has a name?

Is there a name for a fallacy where you think that if one side is wrong then you assume that the other side must be correct?

There is a balance fallacy where you assume that both sides arguments have their merits, but it’s like the opposite of what I’m asking.

Excluded middle fallacy?

Yes, I think that’s it.

This. or false dichotomy, or false binary, or black-and-white thinking, or “You’re either with us, or against us”

That’s what I was going to post.

Well, if it’s not the Excluded Middle Fallacy, it must be one of those, right?

It’s somewhere in that heap, sure :wink:

There’s also zero-sum bias.

Maybe even splitting.