Deniability is not the primary driver for, or purpose of, proxy wars. They are a means of escalation management for great powers, and post-WWII, a way for nuclear armed states to go to a version of war, that doesn’t carry a high risk of nuclear war.
And even in situations where deniability is a factor, that doesn’t apply here. Iran has always been Hezbollah’s primary benefactor, since the organization’s formation, and it’s not a secret that they serve as a proxy force.
The only deniability is the face saving kind, to again, help escalation management for the great powers.
If you walked into a conversation with someone telling flat earthers that the Earth was actually round, would you get pissy with them, ask for their sources, defend the flat earthers, and then tell the round earth advocate to get off their high horse because they’re not the smartest person in the room?
If we were discussing the pros and cons of certain political systems, or other subjective topics, I would agree with you, but we aren’t.
So, you jumped in to white knight for the people who are objectively wrong. Does that make you feel morally superior?