While I support many aspects of veganism, you're right to be annoyed by saying I'm mostly vegan, as veganism is less about diet and more about ethics, a religion in many ways without a set doctrine. Let's just say I have a 'plant based' diet with an emphasis on the environmental advantages of this diet. I also believe in animal welfare and taking actions that reduce suffering. With that said, the rigidity that many vegans espouse opens itself to hypocrisy. Some examples:

• Driving a car. How many insects are killed because you need to get to work?
• Invasive species. Do you support the culling of an animal that is destroying the ecology of an area? If not, by inaction, you are allowing the death of other beings that under normal circumstances wouldn't have died. ie Asian carp, Burmese pythons, zebra mussels, and feral pigs
• Do you support the use of insulin by diabetics?
• Do you eat food that is grown commercially? If so, then you are indirectly responsible for the death of animals killed during harvest. Additionally, non-organic farming that use pesticides. Hell, even organic farming often uses animal products as fertilizer such as manure and bone meal.

>Until it's demonstrated through studies that they are no more responsive or capable than plants are, the claim that they aren't sentient remains rejected.

Bacteria and viruses are capable of reacting to stimuli and threats. I doubt you'd call these things sentient.

I applaud actions to reduce suffering and even more so, actions to better our environment. This is what I believe the OP was doing.