1) Because the Constitution is not nearly as restrictive as Ron Paul would have us believe. It does enumerate a number of specific powers, but adds "To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers" which allows for much latitude to what is allowed to do.
2a) because there is no violation.
2b) because requiring an amendment (which requires several years at a minimum to pass) for the normal day-to-day actions of the Congress, which so gridlock the national government, as to force to destruction. (IOW, Why do you hate America?)
If the malware purveyors have broken the law, let the government prosecute them as needed.
That's much like say, "we don't need firefighters; we'll just put the arsonists in jail"
Private companies are motivated by profit.
And governments are motivated by power.
I know which I prefer.
ahem... Profit is the CAUSE of most malware....