It sounds like you agree that population levels on Earth are unsustainable and reducing them would help to preserve the environment.

Now certainly you can see why your ideas may be a little harder to accept as the scientific fact that human activity at even much smaller levels as today's population has caused terrible environmental destruction, extinction, etc., and with a lot more room to disagree, but so long as you approach the conversations humbly and with a willingness to consider differing opinions as you would have people consider your opinion I sympathize. Some people just react irrationally.