Because, that really is what is being demanded of them:

Apparently the word has come down from the White House to Democrats across the nation, get in line behind the Obama Administration on gun control. The National Conference of Democratic Mayors are now threatening to have their police departments boycott the purchase of guns from manufacturers who won’t adhere to the Obama Administration’s strictures.

The mayors are going to grade the manufacturers on their record of support vis-à-vis Obama’s plans for gun control, including universal background checks, the elimination of high-capacity magazines and sharing information on crime and mental health.

So, to those brave men and women in blue, who patrol the streets of Chicago, NY, LA, DC, et al, be advised: To satisfy political posturing, you will henceforth only carry black-powder rifles and 5-shot revolvers. Oh wait! Since the revolvers are mostly made by gun manufacturers who also make pistols holding more than 10 rounds, and “assault rifles”, they’re out, too.

Keep your powder dry!