For 104 episodes, everyone was rooting for one couple or another, and they gave a giant "fuck you" to almost all of them, even the ones like Takari with extremely strong hintings. Some of us are still pissed off about that.
The rest feel it distracts from a touching and beautiful ending with Oikawa's turning into butterflies. Or haet the lulzy jobs everyone was given.
It was the greatest troll ever, and were it any other series I would point and laugh, but digimon's the kind of beautiful, amazing show that people just get annoyed.