There were many different reasons people opposed the message about Jesus. In our passage for today, we hear about one we don't think of often. In this passage the silver-smith lobby encourages a demonstration against Christian teachers because they worry the spread of the Christian faith will take away from those who use statues to worship other gods. They think about this danger both from a religious and financial standpoint, since their livelihood came from building images of the goddess who was popular in Ephesus.
The other side that is interesting is seeing how the government reacts. The town clerk addresses the crowd and basically argues that the government's job is to promote peace. Christians are not a threat as long as they aren't disrespectful to other faiths. This is a fun story and a good exploration into one role of government.