The reason municipalities are switching to chloramine is because, unlike chlorine, it doesn't dissipate... it's the chemical that keeps on giving, lol!
I'm not sure exactly what effects it has on plants, but if it were really harmful, most people on city water would have fried yards!
It may be fine for plants in the ground, or large pots, but if I was having trouble in small pots, and on city water, that's the first thing I would change.
I'm not sure I'd use it for a hydro grow, especially since there are plenty of cheap filters to take it out.
I don't really understand this: "If i was going to brew a compost tea and i wanted to ensure its bio-activity i would use treated water." Part of chlorine/chloramine's purpose is to cut down on bio-activity.
I use well and rain water, so luckily, that's one less thing my plants have to worry about... but, I give them plenty of other things to have to deal with, lol!