That article pretty much just rehashes what I said, and doesn't touch on what you said about "being made with a starter" so I'm not really clear on why you linked it.

The legal requirements for Tennessee Whiskey are the same as for bourbon + it must be made in Tennessee + charcoal filtering

And since bourbon can be made anywhere in the US, and at least until the next civil war kicks off, Tennessee is still in the US

And since the legal definition for bourbon doesn't say that you can't charcoal filter it, and since it's purpose is to "remove impurities" I think it's safe to say it's not adding any color or flavor which would disqualify it. (And one of the big producers doesn't even need to do it)

I think it's safe to say that Tennessee Whiskey is bourbon. It just checks a couple extra boxes so it can be marketed as "Tennessee Whiskey" because it makes it sound a little extra special.