Critics of the system have every right to be concerned. Remember, after 9/11, London bombings and others, governments around the world, especially the US & UK brought in new anti-terrorism laws to combat the fight against terrorism and even back then critics of the new laws came forward and said the new laws will be open to abuse because the police will be able to use the new laws to carry out unrelated checks, searches and arrests but use the new law as their justification for doing so. Both the US & UK governments said this would not happen but guess what, it did and for many years the tabloid press reported on incidents of police abusing their powers in using the new ant-terrorism laws to arrest people for things that was not actually terroism related.
Based on the above, critics of CSAM know that once released, it will be open to abuse, just as the terrorism laws were open to abuse. China is a very good example of why critics are worried. Look at what Google and Apple did when China said to operate in their country, they must comply with their laws. did Google and Apple say they no?, no they didn't, they just made excuses that they have to comply with the countries law. Many of China's law curtail freedoms of their citizens which means it would be more than likely CSAM would be open to abuse.