How did Jodie Foster avoid questions about her personal life for so long?

Maybe they thought it wasn’t relevant in terms of her talent as an actress.

And they were right.

Because from the start this is where she drew a line.
Press are like dogs. They need a firm and consequent hand.
Give them food off the table just once and you created a beggar for life.

She's pretty serious about her work. No matter what her personal life was/is like, she stays all business and keeps focused on the work. That ordeal with Hinkley probably contributed to that.

My guess is maybe the press cut her some slack after the John Hinckley incident, no doubt combined with a deliberate decision by her to stay out of the spotlight.

Given a certain amount of money, I think it's probably pretty easy to avoid the media digging into your business. Don't live in Hollywood and seek out attention Don't be sexually promiscuous or promote a phony sexuality for image. It probably also helped that she was cute, but not exactly bombshell known for her sexuality.

I'd guess all the usual insiders knew she was a lesbian and in a committed relationship, which ultimately isn't that scandalous or interesting. It's only interesting if she's fronting a fake boyfriend/husband, has a merry go round of partners or positions herself as a sex object/bombshell.

She never sought out more attention than she wanted.

She kept her private life very private.

When someone did ask about her private life, she didn't answer. After a while people got the hint.

On top of that, I think the media and most of the public did cut her some slack after the John Hinkley situation. She was very young and probably felt some guilt over the fact that the President and several others got shot by some psycho who wanted to impress her. So, she probably became very guarded at that point, and everyone understood why and seldom pressed her on it.

Private person

Works hard and seldom complains. Stays private for the most part.

It's because no-one is really bothered.
Back then, media intrusion was fairly minimal and all audiences wanted were good movies.

Nowadays, it's only the celebrities 'outing' themselves (because apparently they think people are bothered?)

Which (neatly) brings me back to my initial point