This kind of cartoon is likely to be liked by other vegans, but unlikely to convert anyone else to your cause.
There's no need to get defensive and personal because the truth upsets you. It's not my cause, it's the cause of the environment and the abused who can't speak. And I certainly hope no one "converts" to anything based on a single cartoon, that'd be irrational just like the people depicted in the cartoon itself. I hope that anyone who decides to be part of the positive change does it because they've researched the science that supports it and have a drop of conscience and compassion in them to take action.
A good marketing campaign, maybe. Every time I see someone trying to convince people to switch to veganism, it's either "you should feel bad for eating meat" or "look at these studies that prove how eating meat is bad for you". Most people are not going to stop eating meat just because a doctor told them to, and the idea that an omnivorous diet is somehow immoral is alien to our society, so guilt won't be very effective either. Shock videos can help, especially with young people that haven't yet become too apathetic to the world around them. People of all ages who already take care of themselves are more likely to be receptive to a message that emphasises the health benefits of a vegan diet. In general, you want to have a positive message, something that makes people feel good about themselves for making a certain choice. You have to think of veganism as a product and ask yourself what's the best way to sell it.
Thanks for the constructive reply. I really appreciate it. Do you mean like what PETA, Mercy for Animals and many other animal rights and welfare organizations are doing? Has any of their work appealed to you?A good marketing campaign, maybe.