I have encountered this idea in the past when I used to be more active on Yahoo! answers, there the Far Right, most of whom supported the BNP being active in spreading hatred and intolerance. But that was several years ago while now, I am encountering intolerance and fear once more.
The term White Genocide is an emotive one. I live in the UK and there is a city where the white population is now less than 50%. But, while it may appear to be so, it is not white genocide.
KILLING MEMBERS OF A GROUP - Violence occurs and this affects all skin colours, but I have yet to see selective ethnic cleansing of white people in the UK or elsewhere. It has happened in the past, this being in Nazi occupied Europe in the Second World War as well as in Bosnia which sadly was more recently.
CAUSING SERIOUS BODILY OR MENTAL HARM TO MEMBERS OF THE GROUP - Again, no evidence exists of that happening to white people at the expense of others now in the way it happened in Nazi Germany before the Final Solution.
DELIBERATELY INFLICTING ON THE GROUP CONDITIONS OF LIFE CALCULATED TO BRING ABOUT ITS PHYSICAL DESTRUCTION IN WHOLE OR IN PART - Places like the Warsaw Ghetto.
IMPOSING MEASURES INTENDED TO PREVENT BIRTHS WITHIN THE GROUP - The Nazi's forced black people to be sterilised.
FORCIBLY TRANSFERRING CHILDREN OF THE GROUP TO ANOTHER GROUP - While genocide wasn't the aim, this has happened with Aborigines in Australia.
And one issue that white supremacists bring up is how the issue of forced immigration and assimilation in Tibet is viewed by many to be genocide. There is no doubt to me that the intention of China is to destroy the regional identity and culture of Tibet. However in Tibet, the people there have no choice in this matter whereas in the democracies of the west, people have a say and as yet, since 1933 no major democracy has voted to permanently end immigration. This means that immigration is not forced (though it may be against the wishes of a minority) and people have the right to retain their languages and beliefs.
If you read this and think I'm wrong, please comment so I have the opportunity to learn. x