When setting up Sponsored Display targeting, Amazon prefills some category/product/audience suggestions by default. Rawlings recommends clearing ("X-ing out") these prefilled selections and manually reselecting targets, rather than accepting them as-is — otherwise you risk unintentionally advertising to categories or audiences you didn't actually choose.
Failing to clear Amazon's prefilled/suggested targets before adding your own means the campaign ends up advertising to audiences you never intentionally selected, silently diluting the targeting you meant to run.
"I recommend Xing those out so that you can select your own and make sure you do that cuz if you don't do that and you add a few you're actually advertising to different audiences that you didn't even mean to or didn't even select"