Let me be super clear here: nobody is entitled to use other people’s stuff to make trouble or potentially harm society. Not your mother’s house; not Facebook’s messenger. If anyone gets to use anyone else’s stuff, it is at the owner’s pleasure and under their conditions.
So no?
The person you reply to is a 7 year old account in good standing.
Also let me give you another example: licensed medical doctors being unable to have a technical discussion between themselves about Ivermectin in one channel and having to move elsewhere.
In general you can't distinguish but fortunately that doesn't matter. Facebook doesn't block lies, it blocks "known misinformation". The information in the linked article is known to be false, and it is harmful, so it's blocked.