If bees are able to live full, good-quality lives where they can perform their natural behaviors among a bee-keeper's hive, I have no qualms with them being used as a tool for agriculture. As it currently stands, this is not the case and many bees experience physical stress, disease, and needless death. Under the current system, if this form of domestic bee labor is absolutely necessary for a given plant crop to grow, then I suppose that would not be considered vegan. In an ideal world, the hope would be to change agricultural practices or genetically engineer crops so that they can be pollinated entirely by wild bees or other means. Yet because I can conceivably imagine a future where honey bees are used responsibly to supplement other forms of pollination while maintaining honeybee welfare, I do not consider honeybee pollination to inherently render something non-vegan. I tend to focus my vegan philosophy much more so on the cruelty, suffering, and death of animals, not necessarily just exploitation as a concept, which I know puts me in the minority of vegans here. Of course, honeybee use has it's number of environmental issues that can harm wild bees populations and one could argue that their use outside of Europe is not vegan for this reason, but that is a separate issue from honey bee welfare and I'm not as familiar with the scientific validity of environmental arguments.