TL;DR: Reddit is removing the option to opt out of ad personalization, targeting ads based on user activity. Some specific ad categories can still be limited, but there's no more opt-out option.
Lol that's more like the end of American consumerism, and while I wholeheartedly agree, that'll take a generation or two at least to decouple from American society. That shit's been going strong here for over 100 years.