He's just not that into it

From Lasok, K.P.E.: The European Court of Justice: practice and procedure, 2nd ed. (London: Butterworths, 1994), p. 197-198:

"Lack of interest
[...]
There is no express requirement that an applicant should show an interest in having the legality of the act in question reviewed in addition to showing that he falls within the category of potential applications as so defined. Nonetheless, it is well established that the admissibilyti of the action is contingent on there being an interest sometimes called a 'legal' interest, in the result of the case [...]."

In this way, even though a party has locus standi to bring a case before the EC courts, his lac of interest in bringing it is an absolute bar to the proceedings "and may be considered by the Court of its own motion".
[...]
"The interest required to support an application has been described as 'legitimate, present, vested and sufficiently clear' [...] The basic requirement is that the action, if successful, will lead to a change in the applicant's position; [...]"

"[S]ufficient interest may exist if the circumstances are likely to recur, and the judgment will therefore cause the defendant to avoid re-creating or repeating an unlawful situation, or if the judgment will affect other proceedings."