Article that explains in part why those cops look the way they do:
7 Ways ...
For the tl;dr crowd (kinda) or link-shy:
"...all of those anti-drug policies continued, but were supplemented by new war on terrorism endeavors -- yet more efforts to make America's cops look, act and fight like soldiers."
"1.
Pentagon Giveaways
In 1997, Congress added a section to a defense appropriations bill creating an agency to transfer surplus military gear to state and local police departments."
"2.
Byrne Grants
...Over the years, these grants have created multi-jurisdictional anti-drug and anti-gang task forces all over the country. ...
The George W. Bush administration had actually begun phasing out the Byrne program. It had been funded at a half-billion dollars per year through most of the Clinton presidency. By the time he left office in 2008, Bush had pared it to $170 million a year. But the grants have long been a favorite of Vice President Joe Biden. "
"3.
COPS Grants
The Community Oriented Policing Services, or COPS, program has followed a similar trajectory...Just as it had with Byrne grants, the Bush administration was phasing out the COPS program in the 2000s. But like the Byrne grants, COPS grants have long been a favorite of Biden."
"4.
DHS Anti-Terror Grants
The Department of Homeland Security has been giving its own grants to police agencies. These grants have been used to purchase military-grade equipment in the name of fighting terrorism."
"5.
Medical Marijuana Raids
Despite campaign promises to the contrary, Obama has not only continued the Bush and Clinton administration policy of sending SWAT teams to raid medical marijuana growers, shops, and dispensaries in states that have legalized the drug, he appears to have significantly increased enforcement."
"6.
Heavy-Handed Police Tactics
...The Obama administration has defended the use of aggressive, militaristic police actions in court. In the case Avina v. U.S., DEA agents pointed their guns at an 11-year-old and a 14-year-old during a drug raid on the wrong house. The agents had apparently mistaken the license plate of a suspected drug trafficker for the plate on a car owned by Thomas Avina. Obama's Justice Department argued in federal court that the lawsuit should be dismissed before being heard by a jury because the agents’ actions were not unreasonable."
"7.
Asset Forfeiture
Under the policy of civil asset forfeiture, the government can seize any cash, cars, houses, or other property that law enforcement can reasonably connect to a crime -- usually a drug crime ... the policy has been lucrative for police agencies, and has been a huge contributor to the growth and use of SWAT teams to serve drug warrants ... A number of states have tried to curb forfeiture abuses by requiring that proceeds from seizures go to schools, or to a general fund. But under the Justice Department's equitable sharing program, a local police agency simply needs to ask the DEA for assistance with a raid. The operation then becomes federal, and is governed by federal law ... Under Obama, forfeiture has flourished ... Obama has fought for broad asset forfeiture powers in court, even for local governments."