Got nothing to do with being humanoid.

Bipedal predators are a rounding error, probably the most effective hunter/killer robot would be dog shaped and medium dog sized, with a back mounted turret.

Give it pack tactics, with radio comms....

If you consider the mentality of fascist dictators, the concept of an ever obedient non thinking workforce/army is very appealing. That's why.

Could it end badly even for them? Sure, but heck, if they don't make the human race ending robots, someone else will.

Why the hell does anyone think it's still a good idea to make robots that are significantly stronger than humans?

So they can easily do tasks better than a human or that a human could not possibly do. Like moving heavy furniture unaided.

The strongest wisdom I have learned in life is that if humans can do it, they will. Ethics can never prevent something from arising; only physics.