It is very simple to explain everything here. The slaves had no rights, they belonged to their master. Were the same as other things or animals. Sometimes even livestock was more valuable than slaves. So, if the slaves did not have any rights, and they were just property, then it is logical that the punishment for theft of any property was the same. Stealing a slave in Egypt is like stealing now, for example, a tractor. But slaves for theft were punished very cruelly and indicatively, up to the death penalty.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.