As God provided the Jews with the Torah in order for them to individual interpretations, there is no perfect teaching of halacha, as it is based on varying opinions. One's opinion cannot be more acceptable than another since it depends on each person, however, the halacha has to come from the word of God. Since the House of the Hillel included both their own interpretation and the House of Shammai's, it makes the House of Hillel more accepting of different views of halacha, which is why God chose them, as their teachings are more objective.
