The way I read it, the source of that "explanation" was intended to be satirical, not acknowledging that such a video exists. Whether because he's a fool or just plain devious (I go for the latter), Johnson used Booman's quote to make the same spurious point you did.

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The Republicans are past masters of using race-baiting and attacks on immigrant and imported workers to win elections. They've already done polling and focus groups to see just how much of it they can get away with and maintain ‘deniability’. Their tactics are similar to those of the Tories and BNP who hope to ride a wave of racist islamophobia against muslims to electoral victory. In both the United States and England race baiting leads to violence. The anti-Irish hate speech of the DUP led to a decades long campaign of violence that claimed thousands of lives.

http://www.guardian.co.uk/commentisfree/2007/dec/20/thinktanks.conservatives.

http://news.bbc.co.uk/2/hi/uk_news/northern_ireland/7162580.stm

The use of hate speech is a deliberate tactic to “divide and rule” and is used extensively by rightwing and ultraright parties and by depraved cultists like the Pope, Ian Paisley, Pat Robertson and other bible fascists, as well as by murdering swine like ayatollah Al-Sistani.

Our only effective strategy to combat it and at the same time undercut the religious bigotry found among some immigrants is for the GLBT communities to condemn all kinds’ bigotry and racism. Instead of joining in the attacks on minorities and immigrants, which is what the Tories and the Republicans want us to do, we should seek out alliances with all the victims of bigotry and racism.

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