Wow I looked at this for a solid 10 seconds before seeing the "no thanks" and that was even with your bright red arrow pointing at it. The must have user tested this to hell to find the absolute perfect combination of design elements
This is the "trick you into signing up" page that is inserted if you are not currently a prime member.
I've been clicking the "no-thanks" link for years -- as I've never signed up for, nor ever wanted to sign up for, amazon prime.
But, as I know it is going to show up, I'm not surprised by it in the least, and I know where to go to get past it without accidentally signing up for prime. Maybe the FCC complaint might finally make this nice dark pattern example finally go away.
If I remember correctly, they've also moved around the "No thanks" over the years. I seem to remember the "No thanks" option being below the "Enjoy Prime for FREE for blah ..." area a while back. I could swear the prompt changes sometimes between this more standard screenshot above, and some weird pitch geared specifically towards college students, where the "No thanks" option is considerably harder to see.
I was trying to reproduce the prompt that I was thinking of and found an equally obnoxious prompt:
Which defaults to trying to steal any gift card balance you have in order to pay for Prime.
I knew that Amazon was awful, but it's really gotten so far out of hand that it's surprising they haven't had the sort of legal trouble Microsoft had back in '98.