This is all very fine to want, but it's an entirely different conception of government than the one described in the constitution. It's a government much closer to the one in Russia, or China, or Turkey, or North Korea. While it may be used to, in part, fight crime, the line item that justifies the surveillance state is the ability to invest in a guarantee of power.
Trying to turn the US into this state is just going to lead to abuse of power, abuse of people without voices, and a much more wasteful budget: infrastructure spending by investment in paranoia, with a return of more power by fear. Literally government by terrorism.
While I'm sympathetic to your point, it can be taken too far. Government does provide security to its citizens, and it does that partly by gaining prior intelligence about suspicious activities. Some things should be investigated - if someone posted online about committing murder, in detail and with clear plans, I'd hope law enforcement would check it out.
When you look at successful police operations that have prevented terrorism, a lot of it comes down to luck. Someone had an informant who heard someone say something about a bomb.
There just simply aren't enough police in the US to follow-up on every suspicious activity. Particularly now when even mundane activities can be regarded as suspicious.
There is just another form of extrajudicial population control. They are using this as a way to justify arbitrarily rounding up people who have long wanted to be free of Chinese rule.
Same for someone who want to purchase large quality of fertilizer for no real needs.