Yes, Brita filters should be capable of removing chloramine just like any other activated carbon filter. The problem is that chloramine does require a longer contact time with the carbon to gain that removal. I was just plowing through some of my class notes from my college activated carbon course and found a study that showed that to achieve high removal of choramine with activated carbon, the Empty Bed Contact Time had to be at least 6 minutes. What that means is that if your carbon canister had an internal volume of a gallon, that the flow rate would have to be 1/6 gallons per minute to effectively remove chloramine.
You should recognize that most filter canisters are WAY less than a gallon in volume, so the allowable flow rate would be far less than the 1/6 (one sixth) gpm calculated above. Knowing that most users aren't going to run their filter that slowly, I suppose that Brita appropriately denies that their filter works on chloramine.
I have to admit that I had been stating that a 10-inch activated carbon filter would remove chloramine when run at 1 gpm. It looks like I should revise my allowable flow rate downward when chloramines are involved.
PS: I do know that the 10-inch AC filter is quite effective in removing chlorine when run at 1 gpm.
Sorry for the bad news filter users!