First off don't trust someone like Tucker on technology things. Second it is very likely the issue was human security failure. It almost always is. We are the weakest point of failure.

Also very possible the message was SMS and not over signal. They used to have this feature. If it were an actual weakness in Signal he should contact the devs and report it so they can resolve it.

I don't trust Tucker either. We should not be basing our opinions on media figures period. Even if you agree with them. Trust the math or don't use Signal.