From the reddit post:
"Most users just accept the defaults they’re given"
[...]
"There is a toggle to turn it off because some people object to advertising irrespective of the privacy properties"
Bad defaults are only bad if other people set them.
@alarith @denschub there is definitely a discussion of harm here, the harm of not turning it on is... Zero. The harm of turning it on by default is that people who previously weren't being tracked now are. Not zero.