They (anyone) can not make laws or rules retrospective. I expect that had Ferrari been in actual breach of the rule it would have been called out, but if they used 'weasel words' (and good luck to them) to get an illegal result without actually crossing the boundary, due to FIA not being clear enough with the wording, then the result has to be 'right, you win, but stop doing it from this date on'.
All teams at all times are looking to circumvent the wording of rules, there is no such thing as 'the spirit of the rule' except in high court, where The mischief of the law is examined, then re written if it is not tight enough