Take the ego, judgment, and “how things should be” out of it. This is about how to effectively get results as the sender. And it works.
We all have this choice of principle versus effectiveness. If you would like to go with the strategy of thinking the receiver is self-centered, and you should have to only send one email, then good luck. In today’s world you will not have as effective a reply conversion rate as someone else who sends three emails.
I know this is controversial, so everyone is free to attempt the first strategy.