No, its not centralisation. One can create other shitcoins or split the chain but needs to fight it out with SV miners, by putting in their own money where their mouth is & doing PoW
Of it is only a couple pools mining CSW's ShitVision coin then it is centralised. BSV can fork off and take its mining power. BCH doesnt need them.
You still don't understand what centralisation is. It is power of some entity to prevent others doing what they are doing, its having one rule for one entity & another rule for others