Suppose some party had his identity linked to some bitcoin cash address. Couldn't a soft-fork be used to freeze his funds as been done here?
Yes, but it would require a large portion of PoW miners to conspire to censor transactions. That's unlikely because censored users could also increase their transaction fees to tip the miner incentives.
This is more likely to occur on Bitcoin Cash than Bitcoin, because Bitcoin Cash is choosing a path of greater miner centralization. Bitcoin is God... for now.