I usually just get PigPoopBalls and a bunch of insults.

Don’t try to point out why they are wrong, but rather why you believe what you believe. And when they tell you why they believe what they do, no matter how ridiculous it might seem, respect their opinion and explain which points exactly you disagree with and why.

I think the idea of trying to convince the other is flawed in itself. It implies that you are right and they are wrong. Approach any conversation with that mindset, and neither their nor your opinion will change.

Instead, try to see a discussion as a way to exchange perspectives with the goal of finding the truth. Only if you are open to the idea of changing your mind can you hope to change that of your conversation partner.