Its because every country & currency bloc is manipulating their currency. Only a few of those get designated as currency manipulators for political convenience

Its because every country & currency bloc is manipulating their currency. Only a few of those get designated as currency manipulators for political convenience. It is that simple. The primary tool to manipulate the currency is by introducing additional money into the supply. The primary way to do that is to buy bonds at a premium price (where whoever previously owned the bond and sold it now has new money that didn't exist before, this trickles throughout the system diluting the value of the currency for everyone else). Pushing up the price of bonds pushes down the yield. Newly issued bonds are done at the market price and tolerance (what the market can bear). So if the prevailing rate is 0% or -0.5%, newly issued debt in the same risk range yields 0% or -0.5% too.