They are arbitrary only in the sense that, sans a religion's God laying down ethics from on high, all ethics are arbitrary human creation.

But we care about ethics all the same. Engineers care about ethics because if they do not, they kill people. Civil engineers care because faulty work kills people. Electrical engineers care because faulty work kills people. Mechanical engineers care because faulty work kills people.

And as software engineers, we should care because our careless work kills people.

And if we do not care, the government will force our hand. And they will not listen to pleas for them to be reasonable.

Software engineers abused people's personal data, the EU's GDPR has outlawed using all but the absolute minimum personal data. Meta has been told in court by the CJEU that advertising is not an acceptable use of personal data, even if needed to pay the bills. Ad-tech is a doomed industry.

So it's your choice. Start caring about ethics. Or the government locks our field in so much regulatory gridlock that you will wish they just outlawed it entirely.