Why are kiwis not considered suitable for vegans?

It's about bees.

Kiwifruit aren't the only food that breaks this rule. So do almonds and avocados, among others.

Kiwifruit, like most commercially produced fruits, are generally grown in monocultures where they are the only crop grown on a farm and may be the only crop grown in the area. This poses a problem.

Kiwi vines come in both male and female varieties, with the male producing pollen and the female producing fruit. To get kiwis later in the season, the female flowers must be exposed to pollen. This is what bees do: they carry pollen from male flowers to female flowers while collecting nectar.

The problem is that the bees cannot live near the kiwis. They would starve to death because the flowers (and associated nectar) are only around for a short period of time each year. As such, kiwi growers hire beekeepers to bring in hives during the blooming season. The beekeeper moves the hives to different crops throughout the year. In a natural environment, different flowers (many of them non-agricultural) bloom at different times, allowing bees to forage in all seasons except winter.

And many vegans oppose this use of animals to produce fruit. They also do not eat honey.