[throwaway478484]

If Google’s services can respond to queries, they must be able to read them.

If A uses a cereal box cipher and B has a cereal box cipher, B can can make sense of encoded messages A sends them, A can ask about the weather, and B can reply with an encoded response that A can decode and read. B is able to read A’s decoded query, and B knew what the weather was, and responded to A with that information.

Security is not magic.

[eynsham]

What do you think fully homomorphic encryption is, then?

[NoMoreNicksLeft]

This is pointless, but I'll try anyway.

Yes, they can read both. But it's just gobbledygook to them. If you send them a "nonsense" query, they can reply with a "nonsense" response which is actually carefully computed to be something you can make sense of. But they can't make sense of it other than that it should be a relevant to the query you sent them.

[NoImmatureAdHom]

The thing that you find magical is not only actually possible but implemented and in use! What a day for you! Enjoy it, this is a rare event :-D