What do you mean you'll have no impact?? You realised for every piece of meat you don't eat, that's less demand for an animal to be killed right? Not to mention the significant reduction in carbon emissions. That's not including the change you impart on others. I was convinced to go vegan, and I've convinced others as well.

Your first point is just straight out wrong. Do you vote? Or is the fact your vote doesn't single handedly decide the election enough to dissuade? Your logic could be used by a murderer to go "well, there's murder in the world that I can't stop, so I might as well keep murdering!". Very very broken logic.

I agree with you the only argument against veganism is "I don't care". But then you must accept you are a person who knowingly commits bas deeds, deeds you could easily stop today, but choose not to out of greed.

And your third point is just weird? If you accept that scientific discourse agreed abstaining from meat has a worldly positive impact, isn't that enough? Or is the scientifically supported increase in life expectancy associated with veganism not enough?