I think you already got one great reply, I have just one thing to add to it: your post literally presupposes a 1.0 version of this software that never has its feature set expanded. I don't think that's a reasonable assumption. After all, with 1.0 the goal of catching this class of person is barely achieved. They'll likely arrest people, 99% of whom are just CSAM jpeg collectors who get an extra kick out of viewing a class of image that is super illegal. And nothing more.
Then for version 2.0, they'll realize the INTERPOL, FBI, whatever can provide them a combo hash plus one string of text that can nail a known active producer. The holy grail. This small feature add to get so much closer to the original "moral goal" will prove too appealing to pass up. Now all the code is in place for the govt to pass over requests for data pinpointing mere common criminals.
Then for version 2.0, they'll realize the INTERPOL, FBI, whatever can provide them a combo hash plus one string of text that can nail a known active producer. The holy grail. This small feature add to get so much closer to the original "moral goal" will prove too appealing to pass up. Now all the code is in place for the govt to pass over requests for data pinpointing mere common criminals.