Vegans that I've met usually reject honey, because our consumption of honey requires the use of bees. However, many plants require insects for pollination, and those plants are still OK to eat in a vegan diet. What are the criteria based on which plant-based food is accepted or rejected in a vegan diet? Is the defining difference that bees collect honey to eat, or are there other factors?
As leancz said, there isn't one answer to this. An argument I heard from extreme vegans:
The difference in your example is that bees are often harmed when collecting honey, and also you "steal" the basis of their habitation as well as for new offspring, while relying on their pollination 1) is indispensable and 2) doesn't harm them but, on the contrary, it's essential to their survival (while the crop of the pollenised plant isn't).
Edit: I hereby present a somewhat suspicious link to Why honey is not vegan. Please don't hold me liable.
The terms vegan and vegetarian have fairly loose definitions. There are vegetarians who eat fish and wear leather, vegans who go to extremes and vegans who are pragmatic. It is pretty much an individual choice about what one consumes and which term one applies to oneself. You could compare it to traits of democrats and republicans or empiricists and rationalists.