I have this feeling that the Monitor was being confrontational with Oliver "just because" because there is no way that Barry and Kara were actually going to die despite Clark's assertion that it was inevitable that they would, and that whatever "deal" Oliver made was what was going to happen anyway.
BTW, Mark Pedowitz has said that there are no plans to end any of the Arrowverse series any time in the near future, so the CoIE event is being done because it's a story that the writers and producers have had "baked" into their universe for 4 years, not as a way to end a series or kill off characters.
BTW, Mark Pedowitz has said that there are no plans to end any of the Arrowverse series any time in the near future, so the CoIE event is being done because it's a story that the writers and producers have had "baked" into their universe for 4 years, not as a way to end a series or kill off characters.