As someone who runs facebook ads for ecomm, repeated targeting are a core part of making facebook ads profitable.

You'll almost never make money by running a simple, one-step ad with a link to your website.

What we do is to target a group of people with a simple ad, then people who engage with or leave impressions on that ad will be run into a second ad, and so on and so forth until you finally funnel them into a conversion ad (for example, a discount) to try to convert those "warmed up" leads. All the campaigns leading up to the conversion ad aren't profitable, then you make all your money on the conversion ad.

So advertisers actually intentionally target you repeatedly, most people it just annoys but for the subset of people that are actually interested in your product, it can work. Familiarity and repeated visibility seems to lead to a sort of trust for certain people.