I thought this was just a cynical take at first, but it prompted me to read the very brief press release attached to the OPs article. Your answer actually seems to be correct. Apologies!

It sounds like this case was actually brought to court as a matter of unnecessary dara collection under GDPR and said if this data has no ligitimate use that it violates data minimalism requirements and should be discontinued. The rail system said they used it to tailor language used to the customer, and the courts decided that generic language could be used adequately without any gendering and to remove the question of gender.

the Court reiterates that, for data processing to be regarded as necessary for the performance of a contract, that processing must be objectively indispensable in order to enable the proper performance of that contract. In that context, the Court finds that personalisation of the commercial communication based on presumed gender identity according to a customer’s title does not appear to be objectively indispensable in order to enable the proper performance of a rail transport contract. The railway undertaking could choose to communicate based on generic, inclusive expressions when addressing a customer, which have no correlation with the presumed gender identity of those customers. That would be a workable and less intrusive solution.

the fundamental freedoms and rights of those customers can prevail over that legitimate [business] interest, in particular where there is a risk of discrimination on grounds of gender identity.

It’s barely over a page to read, and as someone not covered under GDPR, is very enlightening to see a court actually defend private personal party data seriously. I recommend giving it a full read to anyone interested in data protection.