YOU GAVE THEM YOUR PERMISSION.
Maybe, in the future, read the TOS and Privacy Policies rather than just pressing accept and acting offended when they do EXACTLY what they said they'd do.
Had you done that, you'd also know exactly who has access to that information and, if you read when they notify you of policy updates, who will have access in the future.
Why is this so hard to understand for people? Gmail is not free, you are paying with the information gleaned from it. If you aren't ok with that, start shelling out money.
ARTHUR DENT: Yes! I went round to find them yesterday afternoon. You’d hadn’t exactly gone out of your way to pull much attention to them have you? I mean, like actually telling anybody or anything.
MISTER PROSSER: The plans were on display.
ARTHUR DENT: Ah! And how many members of the public are in the habit of casually dropping around the local planning office of an evening?
MISTER PROSSER: Er – ah!
ARTHUR DENT: It’s not exactly a noted social venue is it? And even if you had popped in on the off chance that some raving bureaucrat wanted to knock your house down, the plans weren’t immediately obvious to the eye were they?
MISTER PROSSER: That depends where you were looking.
ARTHUR DENT: I eventually had to go down to the cellar!
MISTER PROSSER: That’s the display department.
ARTHUR DENT: With a torch!
MISTER PROSSER: The lights, had… probably gone.
ARTHUR DENT: So had the stairs!
MISTER PROSSER: Well you found the notice didn’t you?
ARTHUR DENT: Yes. It was "on display" in the bottom of a locked filing cabinet, stuck in a disused lavatory, with a sign on the door saying “Beware of the Leopard!”. Ever thought of going into advertising?
> Why is this so hard to understand for people?
Because an extremely large amount of money is spent on UX and PR conducted by some of our brightest minds, to make it as hard to understand as possible.
Conflating security and privacy to use 2FA to get phone numbers out of people is a great example. HN and tech news sites were/are awash with security experts telling people to protect their personal information by enriching their identifiers for surveillance companies.