The word 'bigotry' is used a lot. It is mostly used to mean, not

• obstinate devotion to one's own opinions and prejudices, and animosity toward those of differing beliefs
  

but

• agreement with opinions I disagree with
  
  

http://rosecityantifa.weebly.com/1/post/2011/12/event-at-psu-promotes-bigoted-pseudo-environmentalism.html

Here, a group of anti-fascists argue against screening a film because, in it, someone called John Tanton argues that high immigration is bad for the environment. According to them, that's 'bigotry'. This conveniently makes it beyond discussion. so there is no need to try to explain why this view is wrong.

I don't know if John Tanton is a 'white nationalist'. Even if he is, I fail to see why that particular form of identity politics is inherently worse than all the others. I do know that he is a valuable critic of the Southern Poverty Law Center, a much better-funded and effective opponent of free speech than the anti-fascists. An example of the hysteria this organization is capable of generating can be found here:

http://usnews.msnbc.msn.com/_news/2012/03/07/10602763-election-economy-spark-explosive-growth-of-militias

Tanton's critique of the $PLC is here:

http://www.splcreport.com

The anti-fascists accuse the producers of the movie, GrowthBusters: Hooked on Growth, of "promotion of anti-immigrant and neo-Malthusian narratives". This one-liner is no substitute for a critique of the ideas of Thomas Malthus, 18th century population theorist, and inspirer of some of the founders of the Earth First! environmentalist group.

Instead of trying to shut down discussion of the relationship between immigration and the environment, it would be better to attempt to explain why Malthus was wrong.

In a nutshell, he argued that food production expands arithmetically, whereas population expands exponentially (If this generation has 4 children, they will have 8 children, 16 grandchldren, etc.). But there are checks on this process:

"The positive checks include hunger, disease and war; the preventive checks, abortion, birth control, prostitution, postponement of marriage and celibacy" (Wikipedia)

But hunger, disease and war increase population (baby booms), More positively, unlike any other animal, humans have less children, the wealthier they are. That's why Swedish women have fewer children than Guatemalan ones: because they have been liberated from poverty and ignorance by... capitalism. (Surprise, surprise).

As the anti-fascists correctly say: "A false assumption underpinning the population myth is that the primary cause of resource scarcity and environmental destruction is that too many poor people, people of color, immigrants, and people in non-industrialized nations are having too many babies".

But this insight is incompatible with claiming the Malthusian position is a "pseudo-environmentalist narrative" which "places blame squarely on the shoulders of those suffering the most devastating effects of white supremacy, colonialism, patriarchy, and other oppressive policies".

A theory cannot be simultaneously false and pseudo-scientific. If it's meaningful, ie. true or false, why would you be concerned about it 'placing blame' anywhere? Would you reject it if it were true AND politically incorrect?

It would be better to study critiques of the 'Malthusian narrative' from within environmentalism, such as this pamphlet from George Bradford of The Firth Estate:

http://theanarchistlibrary.org/HTML/George_Bradford__How_Deep_is_Deep_Ecology_.html

But this would have two disadvantages from the viewpoint of anti-fascists. In the first place, it would require them to learn the rules of logic, which is hard work. Secondly, and relatedly, it would mean abandoning their opposition to freedom. The $PLC wouldn't be very happy about that.