American managers do not tolerate dissent and that creates culture of saying only yes.

These cultural aspects are always set at the top. The bottom people react to what the leaders do, what they reward and what they punish.

This is the reason. I logged in to basically say the same thing. I used to be this way, and give opinions, but you cause problems over time that ends up with you getting disciplined in subtle ways or fired.

Yeah, it’s hilarious to be having this conversation about MLEs while attributing the bad outcomes to anything other than poorly designed reward functions, i.e. management. If an engineer burned millions on failed training runs because they did a shit job of creating a policy that maximized for the desired outcome, they’d get canned, but that’s just a Tuesday for your average MBA with VC backing.