You'd need to limit the capacity to vote on credibility to people who are members of the community. If you haven't joined, you can't make a judgment about what is or isn't a good faith post, but your own post can be voted by members. Rather than being attached to just the user, it would probably be better if it were referenced to the user per community. Even so, it's essentially karma, and could probably be gamed.
It's news. Would you rather everyone that doesn't support his bullshit just blithely ignore it today in favor of being subject to it for the next four or more years?
Sometimes the news is "a shit person is saying shit things." Turning a blind eye to it is counterproductive.
You set the goalposts at "opposing genocide," so that's still the elephant in the metaphor. I can understand why you think someone might shift the meaning mid-discussion in order to "win," but that's not happening here.
There are two candidates in this presidential election who have a realistic chance of success. One has voiced support for a ceasefire as a step to a two-state solution and concern for Palestinian suffering. The other has expressed the belief that a ceasefire is an unreasonable constraint on Israel, and that a swift, decisive victory is the only solution. One has acknowledged the need for Palestinian self-determination, the other has bragged about figuratively burying Palestine. One has openly stated that they "respect the voice" of pro-Palestinian protestors, the other has signaled that political dissent by "enemies within" will be persecuted.
However, if we've reached the point where you've determined that you are sure you know what I'll say, then this discussion has run its course. Language like that implies that you're preparing for an argument that would very likely either start off circular or quickly regress to that state.
The proverb works when you realize that the Republicans will never allow the first bite to be taken. Not only are they fully endorsing a genocide, they are taking notes and pondering the best way to implement their own here at home. The elephant is the same, but instead of eating you're flirting with being trampled by it.
I view this as a checklist of brand names that require additional assistance in falling off of the trademark cliff and crashing down onto the rocks of common usage below.
Buffalo buffalo buffalo homo Homo sapiens sapiens?