Can you run a stake pool pseudonymously?
Yes you can. The only things I can think of that could be used to identify you would be your public IP address or, DNS records (at least at a public knowledge level of anonymity.) And there are ways to mask those.
Would this be preferred to prevent hacks, enhance DevSecOp, and potentially avoid future KYC requirements from the government?
It will help with preventing targeted attacks on you personally. By that I mean if someone easily knows who you are and that you own a Cardano wallet pledging XXXXX Ada to a stake pool, you become a bigger target for hackers.
As far as Government KYC requirements go, the law is the law, so if you want to be a legal operation, you will need to meet whatever those requirements might be. Therefore if they require that you operate your stake pool as yourself, then you would have to do so.
If the gov recently wants SPOs to KYC their delegators, they must want to KYC the SPO itself?
Yes, but I would imagine that you could do this and keep yourself pseudonymous to the public.
But if everyone is pseudonymous, can the[y] really stop that?
Yes they could. They could just outlaw Cardano if they really wanted to.