I can sort of see why you got banned. You walked in there with no evidence and insulted everyone present. That is not the way to raise social awareness. You should have posted armed with racist quotes and links to interviews that proofed your point. A lot of people aren't confused, just misinformed and very negligent when it comes to their research when supporting an opinion, which isn't exactly hard with the massive polarisation of news sources. You are going to get much further via a process of guided discovery than outright insult, which puts everyone on the defensive. Those people were very certain of their actions - they were supporting someone they felt deserved their support, so your accusation would fall on death ears. If you had to accuse people of something, a bad memory or a lack of information would have been a better bet.

If you'd allow me to give you wording advice (if not, just skip the paragraph) stick to "I" statements as they are least likely to put people on the defence and don't judge others opinions at all or just hint at it - e.g. "I am a little bit confused by the opinions here. I'm afraid I can not support a person who did X and said Y". Engage with facts, not judgement.

Discouraging a debate is pretty shameful, but I'm fairly certain the mod's argument would be that you weren't starting a debate but an argument. I agree that a ban was an overreaction (is it perma or temp?) but you need to work on your ability to disagree without making the room dismiss you instantly due to your wording. I'm personally hoping your ban gets lifted as the Greens desperately need honest critics who don't immediately abandon ship. Just bring more evidence next time to prove your point.

If all fails you could always message the mods and apologise for the tone of your post, but explain that the subject matter strongly irritated you due to the person's history which you felt was being completely ignored. Ask them what they would like to see as a debate starter on a matter like that. If you don't get anything back then you know they have decided on homogeneity over open discourse and have joined the line of parties who have abandoned their base principles.