FWIW I was unaware of the Philip Cross thing, but after digging into it it appears that Wikipedia's arbitration committee imposed an indefinite ban on him from editing any page regarding modern British politics [1] and that after he was found repeatedly violating it, that was upgraded to an indefinite block [2]. Not exculpatory, but at the very least evidence that Wikipedia is capable of taking issues of editor bias seriously and not sweeping it under the rug.