Well @aerelm has a point - if RHA were abusing their 2.0 and people stopped playing other IDs because they mined on Hessians a lot instead it does make sense not to allow these.
GMs have the data - if it's true people stopped playing other factions when one unlawful got (sub 3.0) mining bonuses it's hard to argue with it, and I can't comment as I wasn't around to see it.