Blockchain does not restrict you from creating as many account as you desire from their website provided you can verify your identity and activate it with your mobile phone number.
But following the second opinion why will you need more than one account ? A single account can accommodate all the btc supply.
they dont have rules for multiple accounts but i think they will love if they have alot of users that will sign up on thier platform . one account isnt enough if you are a heavy user because you can easily reach your limits . this why others prefer to make more than one account for back up porpuses especialy if they are afaid to do kyc for upgrading thier account limits .