The colliding String Axions seem to be able to transform into entangled pairs both expelled by the Trapped space horizon into two layers of opposite charged Fermions (+ AND -)
The outside of the horizon is electric negative charged because, the positron seems to be able to make quicker compound positive quarks, being heavier than electrons, which are pushed to the outside of the positive charged horizon.
Conclusion : All Black Holes are Negative charged ( outside) massless Black Holes, however equipped with enormous Casimir Gravity being Axion-String vacuum pressure from outside.