If that is not ethical then the entire Western business world will collapse. This is what "work" accomplishes. You go to work, exchange your time for services

If that is not ethical then the entire Western business world will collapse. This is what "work" accomplishes. You go to work, exchange your time for services done for the company. In exchange, the company gives you money, and yes - extreme amounts of domain knowledge, to the extent that you might be the only person on the planet who knows X topic. Then you take it to the next workplace, to spread it and to innovate. If your current company doesn't like it, they can 1) increase the pay - like pay you so much money that you're willing to stay. or 2) sue you and crush you so that even if you go elsewhere lawyers will be on you everywhere you go. This is how every single person alive on the planet does it. Without knowledge transfer and this type of behaviour, we would never progress beyond the industrial age.