Yes, it's being additive which is why gravity dominates the large-scale structure of the universe (not accounting for dark energy). Electromagnetism likes to cancel out, while gravity likes to build and build.
Actually, althought net charge generally cancels out at large scales, currents and electromagnetic fields likely don't. The argument in the past has generally been that if there are large charge differences they will flow to cancel out. While this does happen, the flow is a current which creates a magnetic field so that when the charges are all finally neutralized, the magnetic field collapses and continues to drive the current. Same principle as a relaxation oscillator but on huge scales. We have observed plasma filaments carrying currents within our solar system and with the vast amount of plasma in the universe and it's excellent conductivity it would seem naive to assume that this wouldn't extend to larger scales. Large scale computer models using Maxwell's equations and the known laws governing plasma show galactic rotation curves that match observation without the need for 'Dark Mater', and unlike 'Dark Mater' or 'Dark Energy', these laws are experimentally verifiable and reproducible in the lab).
IMHO, the assumption that all electromagnetic effects can be ignored at large scales has led us down the ever more bizarre path of Dark Mater, Dark Energy, Cosmic Strings, etc. and many scientists are finally seeing the mountain of evidence that is building to overthrow that assumption. We can see magnetic effects on the sun where massive currents and fields produce CMEs, sunspots are known to be magentically produced phenomena, x-ray emmisions from commets show they have a direct high voltage electrical interaction with the solar environment, ...