[throwawayou812]

They strongly implied that Mueller probably lied because they didn't have to tell the truth and no one could prove it.

The comment literally says:

"They didn't lie, they don't have to. Everything in this indictment may be what they believe happened".

How is that ambiguous in any way?

By definition, they're not facts.

Russia does not extradite its own citizens to the US. That seems to be an undisputed fact. It's also a fact that the people named in this indictment - the indictment being discussed in this thread and the only people relevant to these comments - are Russian citizens. Accordingly, there is a 0% chance that these people will see the inside of a courtroom to litigate these charges.