There's one more thing to add to this liquid-funnel analogy, and that's color intensity.
Color intensity tells you how intense the stressor is on the local structures.
Let's give the hamstrings a yellow color.
The deadlift hits a lot of muscle groups, including the hamstrings. Since the deadlift is a globally intense exercise, it's a large drop into the funnel. And since it hits the hamstrings, there's some yellow in that there drop.
But since there's so much going on in the deadlift, it's not easy to really zone in and target the hamstrings from a pump and contraction perspective.
So the deadlift is a large drop, there's yellow, but it's more of a standard yellow color.
The hamstring curl is a lot simpler exercise, which allows you to focus and engage the hamstrings more. It's not as globally taxing. There's not a huge pour, but the yellow is a much richer yellow (like neon yellow).