The rule are self explanatory so I don't know why you are finding it difficult to comprehend, is just simple when your account is banned all your account that tied to you aren't exempted so they are also ban from the forum even though they don't commit any offense they are automatically ban. Then if you are ban for any reason you are not permitted to go make any other account in this forum if found it would be also be ban automatically for rule violation. So if you own 10 accounts make sure you don't violate any rules with any of them because if 1 account among the 10 is ban is also affects the remaining 9 so treat all with equal rights otherwise your accounts will be ban as well.
from your explanation it means the rule is self contradicting and should be looked into for a rephrase. Because if its not illegal to own multiple accounts then banning all multiple accounts linked to a faulty user should be put in view. The rule can be rephrased to say one account to one user and owning multiple accounts at owners risk. Otherwise this rule is just self contradicting and should be open for review.
There's nothing to be reviewed because the rules are well understandable and self explanatory. If the admin thinks it's worth changing then they will do that but as for my reasoning you don't need to have multiple accounts instead just stick to one account.
The issue with multiple accounts is complex and how they attend to it depends on the reason for the other account(s), how well-established you are on the forum and how you get to use the accounts. It's no news that there are some people on the forum who own their alt accounts and people know them but they do not care about it because they are established well enough, this is even as they join campaigns with it.
Also, the forum encourages people who do not want to express themselves with their main account to open another one to do so without issues. But there is nothing you can explain to some people, once you are not well-established, they would tag the account to render them useless on noticing they are alts if they couldn't get them banned for some reason. So this thing is partial and I urge them to often cool down.
But I don't know what anyone would be doing with three accounts, that's where it gets most ugly.