The thing that concerns me is that they are authorizing Local Governments (law enforcement) to use Defense Intelligence agency personnel and assets. It violates posse comatatis. That and it allows use of Force against normal people in the U.S. It was changed on September 27 of this year. A lot of people that are smarter than me are concerned by it.
I can think of one innocuous reason they might do that. but I have not got the depth or breadth of knowledge to prove or disprove it. It could be used to have military assets to protect someone in concert with the Secret Service.
Otherwise, it's just kind of suspicious and the public concern is a testament to how badly people are distrustful of what our government has seemingly become. Plus election year fears etc.
Here is a link to the document everyone is concerned about.