If you allow one person to get away with this, others may see it as an invitation to do worse. Filings are often a matter of immutable public record and it makes sense that there should be rules as to what goes into them.
What is the act of deciding cases if not a carefully constructed procedure meant to keep order? What is the harm of telling a lawyer to try again, this time following the rules?
You hear the case, however it's presented, and then you decide.
In Swedish courts the court evaluates evidence as it likes. If the judges and sort-of-half-judge-half-jury-Nämdemän agree that something can be concluded, then they're allowed to conclude that.
Obviously procedure is useful, but hearing the complaint is more important.
It's not about procedure for procedure's sake. It's about establishing a precedent that unnecessary content should be left out, so that complaints are always conveyed and heard sincerely.
What is the act of deciding cases if not a carefully constructed procedure meant to keep order? What is the harm of telling a lawyer to try again, this time following the rules?