They opposed Moses because they were on the side of the enslavers, the oppressors; they wanted to use their power to keep the Hebrews under the cruel burden of slavery. There is a pregnant parallel with the false teachers in Ephesus. Paul has just said that these people “creep into households and capture weak women, burdened with sins and led astray by various passions, always learning and never able to arrive at a knowledge of the truth” (2 Timothy 3:6,7). (Incidentally, that doesn’t mean that all women are weak, but just that in the Ephesus of Timothy’s day some were. The false teachers seem to be men, and they are a despicable group. So it’s not an anti-women comment.) The point is that the message of these false teachers enslaves. It takes people with troubled consciences, “burdened with sins”, and it never sets them free. The Gospel redeems, sets free, rescues us from slavery to sin. But false teaching enslaves; it leads to burdened people who can learn and learn and learn but will never know the truth that sets them free. It is all so like the confrontation between Moses the redeemer and the enslaving magicians. That is why it is so appropriate for Paul to compare the conflict in the Ephesus of his day with that ancient conflict in the Egypt of the Pharaohs.