No, the post is claiming that because Tylenol was discovered after autism, it can't be a cause of it. That's flawed logic: it's true that autism must also have some other cause, but it's very possible in principle for things to have multiple causes, so the timeline argument proves nothing.

That's not to say that Dipshit McBrainworm's claim has any sort of merit whatsoever, mind you. It's just that this argument is defective.

"Linked to" means "might cause in some cases". If it's "linked" then it should be at least correlated. The disconnect between the two shows that it isn't.