No debate, no moral discussion
The "killing of the innocents" scene is the only particularly interesting part of this episode, Riker's actions are impossible to justify.
The was no reason to rush to action here. The clones could have been removed to the Enterprise, where they would have matured in safety. Once born (I'm unclear as to any memories they would have had) the two clones could have gone on to live their own lives.
If for some reason the cloning chambers couldn't be moved, they could have remained under the guard of security teams on the surface until they "hatched."
When Will Riker came upon Thomas Riker, there was no immediate move to kill him. How is one situation different from the other?