Phishing has been one of the major problem we are encountering in the Crypto space and something really needs to be done about it, firstly we need to ask how are this hackers about to pull out the email of people from the database of Blockchain.com, or is it possible that they sent a random message to both owners and non owners of Blockchain wallet, because if they are getting their data from Blockchain wallet, then they really need to do something about the security of the information they have in their possession to avoid hackers getting some sensitive details.
It's possible that they got their info elsewhere. Retrieving emails is quite easy - you can get info like that almost anywhere. People give away their email addresses very freely. On average, I think most people regularly receive spam email and its very likely for you to get phishing emails such as these. I'm sure wallet owners know how important and sensitive their information is and how vulnerable they'll be once they are compromised. Anyone just gullible enough would fall for phishing emails.