But this is one case, preflop push, all 3, just different % on opponent call ?
well, this is called the fold equity
and the bottom line is when our fold equity increases our EV decreases. Therefore, we are not interested in increasing our fold equity (read pushing), BUT ! we assume that he will call our bet on flop. To make this assumption work we have to make him commited. In our case we offer him 4:1 odds to call, that actually supports our assumption -> he will have to call in the most of the cases.
So, in terms of EV most profitable scenario for us is to bet the maximum ammount he will call for sure (trying to minimize our fold equity), at the same time making him commited postflop.
So in our case he will be commited if we offer him 4:1 pot odds postflop. Therefore, we have to raise 3x pre-flop (the minimum FE we can afford)
We don`t evaluate the flop, no matter what it brings, since it can not affect our decision anyhow. we are mathematically commited anyway.