Because the scope will be misused, and the data will be given away. It's not like the US government doesn't have an extensive history of privacy & rights abuses

Because the scope will be misused, and the data will be given away. It's not like the US government doesn't have an extensive history of privacy & rights abuses. Tasers were passed as an alternative to shooting a suspect, now they're used routinely for detainment. The various terrorism laws are now being used clearly outside the scope of terrorism (hackers, drugs, etc). The DMCA is being all kinds of abused outside its scope. This is what we're rightly-concerned about.