Earlier quoted context omitted.
I understand why it's hard, but it's very funny to get ads for a product I've bought for weeks/months after completing the purchase. I looked for rain boots, and I bought a pair of rain boots. Getting ads for rain boots now isn't going to drive any purchasing, right? Meta or Alphabet get paid still, so the advertisers are getting hosed.
You might return them and get another brand. Even that little positive signal is often worth the wasted impressions because most of the other signals are either so weak or so competitive.
It's not a positive signal, because for the lifespan of that product I just bought, I have removed myself from the addressable market.