> I think he means that it's not spying or infiltration when the data is already there for everyone to see.

You're not thinking clearly. It is infiltration because the person in question is pretending to be a member of Party A while actually being a supporter of Party B. The person is intending to deny members of Party A the ability to vote for the candidate of their choice in the actual election, forcing them to nominate a candidate that is closer to Party B's platform.

The scientific "data" you're talking about is completely beside the point.

> It's about influence on one area that will affect the whole human species, not just one country, and people (esp politicians) are still very misinformed about the issue. It's about informing everyone, just the opposite of spying.

Again, you're not thinking clearly. Informing people entails honestly discussing your views with them, presenting them with evidence and attempting to rationally convince them of the superiority of your position. In the context of a party primary, that could entail picketing with signs, having a non-violent protest outside, handing out pamphlets to those entering, etc. But that is not what the OP advocated. The OP effectively advocated abandoning that approach and instead opting to deceptively manipulate the political process, undermining the ability of others to honestly participate in it.

You seem to be letting your presuppositions cloud your judgment. You seem to be convinced that those who disagree with you are simply "still very misinformed," and so you're justified to "inform" them by whatever means necessary. (Apologies if this is mischaracterizing your view; please correct me.)

> You make it sound bad, but it's a much better proposition than what it is actually happening: People don't discuss politics, they fight it. It's not treated as a complex set of opinions that have to be reasoned over, but as a sport teams.

You seem to be missing my point. The OP is advocating exactly fighting over discussing. He's saying that, since enough people can't be convinced of his opinion, that those who agree with him should infiltrate the opposition's parties and deny them the use of candidates that disagree with him on this issue by voting down those candidates before they have a chance to be nominated. That's underhanded and dishonest, even a tactic used in espionage.

> Furthermore, the way the voting system is designed, there won't be true parties in a specific position, but they're always reduced to two catch-all options with a very wide and overlapping set of opinions among their members, basically resulting in everybody be unsatisfied with the result.

This is true. So what?

> And the point of the parent is that, since politics are broken, one can contribute to work around it from within.

There are two different ways to work "from within." See below.

> In fact parties evolve this way. The party of Obama was white supremacist related to KKK, and the party of Trump was Lincoln's which freed the slaves of the south. That sounds backwards, doesn't it?

No, it's not backwards, it's the historical reality. And, in fact, many people, including prominent blacks, consider the Democrats' policies to be against the black community's interests today. Of course, such people are derided as "Uncle Toms," rather than engaging seriously with their views.

> (edit: snowwrestler above said it better, parties are not elected, are not part of the constitution and there's nothing inherently wrong or dishonest in trying to change them from within)

Again, there are two ways to work from within. One is to recognize that a party is closest to your own political views, to join it, and then work to convince its members to advocate views closer to your own. Another way is to recognize that a party is closest to your own political views, join it, and then go to the opposing party's primaries, pretend to be one of them, and vote against candidates that are farthest from your own political views. This is the crux of the argument.

> Climate change is not inherently anti-republican or anti-capitalist. The debate is whether to believe it or not, and it is absurd because there is a lot of evidence that it is happening. Humans heavily relied on a stable climate for ~15,000 years to create civilization and still relies on it.

You seem to be missing the point. This thread is not about climate change. If you still think it is, that suggests that you're advocating an ends-justify-the-means approach, which is, again, the whole point: that one side is advocating participating dishonestly, because they think it's justified.