He also isn't making any sense. Why would someone keep in memory all the times something did what they expected? I am absolutely certain that if all buttons were act on press, there would be quite a few painful memories. Every time I encounter act on press it sends me.
This is a typical engineer scenario of trying to reason something as if it is a scientific or engineering fact when in reality it is just a massive personal preference.
In many ways, on release is even worse for shaky hands. Imagine trying to use the vote icon next to this comment with your hand shaking. You need to both click and release without leaving the icon, which is extremely small.
With on click, it only requires lining it up once before executing. There's less follow-through required. And as a best practice, there is an undo button.
