"It's a bill of attainder if you go after Google for violating people's privacy unless you simultaneously — not later, but simultaneously — go after everyone for violating people's privacy" is exactly the same as "It's a bill of attainder if you go after me for X unless you simultaneously — not later, but simultaneously — go after everyone for X."

Whether or not you think they should be able to go after anyone for what Google is doing is a different question, but it's definitely not a bill of attainder to go after one party before others, which was the thing that was called a bill of attainder here ("We'll get to them eventually.. but why shouldn't we go after the biggest business first?").