'You are taking choice away from future generations' is a very meaningless statement that can be applied to everyone, and comes off simply as a concern troll. Most of us Westerners can improve the future in many more significant ways than not eating meat. You are taking choice away from future generations simply by existing and spending resources; by living a cushy western urbanite life and participating in online forums instead of living an isolated rural subsistence life without modern life comforts.
Another poster here wrote that just 5 minutes of driving daily is worse for environment/climate than any possible diet style one might be following. So a vegan that drives 5 min daily affects the environment and climate worse than a meat eater who cycles to work.
As for me, no, I do not have a moral duty to be honest about my values, and your concern troll did not work. I feel I have a moral value to take care of myself and my health primarily, and that's why I switched from ideology I followed (veganism based on ethical issues - resource use and animal abuse/suffering) when the ideology proved to be supported by lies about how veganism is healthy and meat-eating is unhealthy. Instead of an ideology, I went with what proved itself to be correct. And I am glad I did.