I've always thought /r/politics modding was bad, but I also never believed the conspiracy theories because the modding was crazy in all directions. /r/politicaldiscussion, on the other hand, just deletes everything that talks against the status quo. A post of mine about the Wells Fargo settlement a while back got deleted. Another post about Clinton's "downballot" funding not actually going to downballot candidates was also deleted. Different mods every time.

The sub as a whole has a ridiculously pro-establishment slant, almost to the point of parody, so just plain old bias wouldn't surprise me. Regardless of reason it's pretty ridiculous.