There was recently topic of anarchist PE. I think that it is rare case that industrial/noise address very direct agenda or works as "spokesmen" of some specific political agenda. Perhaps due fact that such methods often flattens artistic values, and makes music rather tool of politics than art for sake of itself.
It's hard to consider
Brethren as "spokesman" for American Renaissance, but extensive sampling of Jared Taylor and quotes from known sources makes it much less of merely artistic choice, or provocation. Rather tool of spreading such message. Comparing this to for example Deathkey would make it clear example of project that has no connection to "real world politics" or "organizations".
In Finland we have some new projects such as
Straight Arm Salute, which curiously in the first tape release listed many political organizations and parties in their thanks list. Not to mention full length CD album too is far from neutral. Perhaps one is slightly baffled by quoting recently famous mr. Immonen in booklet filled with swastikas and lining up pictures under "great thinkers" slogan, from David Lane to Pentti Linkola. Musically one could perhaps draw lines of old clumsiest Blood Axis, NAOS, and such. Clearly with leaning to nsbm aesthetic than traditions of industrial.
https://www.youtube.com/watch?v=t4nnsMm8st4Another new project
Veri & Maa (Blood & Land) follows traditions of gloomy martial industrial. Very much recycled ideas of genre, but with pretty explicit content. Sampling from mp3 sources of Linkola Interviews isn't sonically very pleasing, but again, music that seems to operate rather as tool of dissemenation of ideas, not as idea of art for sake of good art.
https://www.youtube.com/watch?v=s9s0puTj8y8Examples from other side of political spectrum are perhaps little less obvious, but as example one could think
Performancefiesta 2015 Noise against Hierarchy. Event included performance art, noise, installations and interactive installations. Vegan kitchen. etc. I didn't see any reports of how was for example
Nihilist Waves, who comes from Italy, but apparently lives in Finland?! As far as I have understood, NW has very obvious political motivations and fits well in this very strongly left wing activist & multicultural center environment and no wonder he doesn't seem any connection to "power electronics scene" of Finland? Event could have be quite curious, but I happened to be on other side of Finland at other gig.
https://nihilistwaves.bandcamp.com/album/nazis-make-me-vomitFeelings of art forgetting artistic values and drifting to be tool of ideology or propaganda? In what terms one would approach it? I personally don't think "message" should be separated from experience. Not that one should agree what is being said, but to deconstruct all to pieces and conclude "people don't buy/listen this because music is good, but because..." seems nonsense approach.