Yes, you were expecting too much of the connector. US law requires that all international arriving passengers reclear security before entering the airside part of the terminal. This is mainly because you've had access to your checked baggage, and thus could have picked up items that were not allowed in a carry-on. There is nothing the connector can realistically do about this. Also, like most countries, the US doesn't "trust" security screenings done in other countries, just like how if you're making an international to international connection in Australia, you have to reclear security as well.

The main point of the connector is to allow people coming from domestic flights into terminals 4, 5, 6, and 7 an easy way to walk to TBIT without reclearing security. Going the other way, nothing is forcing you to use the connector checkpoint, you can go upstairs and use the main TBIT one, or walk to terminal 4, 5, 6, or 7 and use whichever checkpoint has the shortest line.