Saying “you’re wrong” is not the same as saying “you don’t know anything about this topic”. Grandparent did the former; you’re accusing them of doing the latte

Saying “you’re wrong” is not the same as saying “you don’t know anything about this topic”. Grandparent did the former; you’re accusing them of doing the latter. Everybody can be wrong about something, no matter how smart / credentialed / experienced they are.