Does this mean that 51% of the miners can call a hardfork for BU, ( I know that is not what they say in the quote, theoritical question)
whereas 95% is needed to activate SegWit?
I know it isn't a X vs X, but these ratios doesn't look right to me.
While Segregated Witness requires super consensus to be accepted, this is impossible to achieve, we can't get 95% consensus on anything.
We can encounter situation where someone manages to force or 'corrupt' 51% of miners and compels them to act against the network (Core).