Ethical behaviour is - or should be - learned and refined over a lifetime, via parents, peers, all levels of education, employers, wider society and one's own contemplation.
I'm suspicious of the inclusion of ethics classes in MBA courses, given the kind of work many MBAs end up doing. I suspect it can create a mindset in which anything you convince yourself is OK according to what you learned in your ethics class is acceptable, which is a very weak and inconsistent standard.
To be clear, I'm fully supportive of the idea that engineers and everyone else in tech companies should behave ethically. I'm just not sure ethics classes will achieve that outcome.
If engineers, or any employees, are behaving unethically, it's because there's a misalignment between the employee's own short-term incentives (i.e., keeping their job, getting a promotion/raise), and societally-beneficial objectives. It'll take more than an ethics class to fix that.