I don’t use work for anything personal. It’s directly annoying because mitm’ing calls to GitHub and other package repos causes packages to blow up a bit.

My complaint isn’t about privacy, it’s about efficiency.

Finance companies do this for regulatory reasons

Worked for a publicly traded energy company that does this.

Do they also block 4G tethering?

I expect the idea is less to prevent any possible threat and is more a) to comply with regulations and b) to log enough data so if somebody does circumvent your legally required measures, they've left enough of a trail to hang themselves.