I never registered any accounts, makes it easier for someone to snag it, all they gotta do is find out your email then you're screwed
so lets go over this exploit,
alice and bob
alice is email is alice@gmail.com
bob is bob@gmail.com
alice asks bob for his email so he can "steal" an account
attempts a password reset on bob@useast but cant access bob@gmail.com so the account is never stolen unless bobs email itself is compromised.
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you ask blizzard for a password reset saying you cant login
bliz asks you for the linked email to send a 2fa to reset the pass. the email provided must match email on record. if no email on record the account is gone and the bliz rep cant reset the pass it will be left to expire. you must supply the correct email and have access.
(you dont have access to email you are locked out)
you never get the 2fa token
account is never stolen
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is bobs email compromised? nope
i dont see the exploit please help

are you talking about social engineering bob with a session hijack or using a rat? then yes that is very easy to pull off and meet the requirements to access the account but this is not normal security conditions. this also assumes bob falls for the malware exploit to compromise the email to access the d2 account.
what am i missing? have you tried and it actually worked? i assume not and you are just repeating what you heard without testing.