Yeah, apparently this has happened every year for the last 4 years so it should be expected really. I know a lot of folks are pretty rattled by it though lol.
And no, as far as I understand they don't have that kind of control over the network. They are simply running a server with the blockchain on it and being rewarded for processing transactions/blocks. And they generally have to come to a consensus on future changes to the blockchain code.
I'm sure somebody with way more experience with the Steem blockchain could chime in here on that though and provide more details of what control they do and don't have.