Yes, Darat. White supremacists have been around for a long time: just like every other possible political and social stance. There is little that is new under the sun: and there is little that completely disappears.
At different times some of those views become difficult of expression; or become more mainstream. The reasons for those shifts are very complex and I do not think anyone knows the "why" of it. There are many theories, none quite satisfying. It is not comfortable to be in such fog because it is very hard to see what is happening, much less the intended and unintended consequences.
For example: I believe the people of this country are not deeply racist: the response to Griffin tends to confirm that, for, at least, that audience. I do not think that audience is atypical. Like most peoples I think that the brits are casually xenophobic, however. So in the past we have seen strong opposition to racism (against Mosely, for example) when it is presented as an overt political platform; alongside signs that said "No Irish" when houses were to let; which didn't bother people all that much. I attribute this to a profound distaste for institutionalised unfairness coupled with a deep commitment to individual freedom in certain arenas.
It was difficult in this country to persuade people that the one is a manifestation of the other: that is no surprise. We are not very good at empathy: if a party or person says "we should not let group x do y" most people will instantly see that is unfair and will oppose it; but if they say we should not let group x do y because they are different in some relevant respect, that is not so obvious. Indirect discrimination is difficult to see even if you are subject to it: and it is very difficult indeed to see it, if you are not.
There has always been an immigrant population in this country: and they have always been subject to discrimination and to acceptance: the balance of these changes with circumstances in obscure ways. So in the 1950's there was a big influx of black people encouraged to come to the UK to meet a labour shortage. Racism was casual ( by which I mean individual rather than organised - though the cumulative effect of that can be "institutionalised racism" as seen at the Met, most famously) at that time: the first generation accepted low status jobs and in most of the country their numbers were low: I read somewhere that if the "other" population is below about 10% they are well tolerated: seen as "exotic", if you like. Above that figure (and I think 10% is too high but I cannot support that view: but above some figure, anyway) that shifts. When such a group stays and their children begin to perceive themselves as native and to demand the rights everyone else has, it becomes a threat. In good economic times that might not be important: in recession it more likely will. As I said, lots of factors.
Anyway. Partly, I think, because of the influence of the analysis provided by the civil rights movement in America, the nature of discrimination was made clearer during the late 50's and later. We are still developing our understanding of those processes and we have made many mistakes: but generally the issue of equality was to the fore at that time and the climate was one of inclusion. "The personal is political" is a slogan primarily attached to feminism, but it applied widely: because it aimed to show how indirect discrimination works. that is more difficult because it challenges our behaviour and not that of rules and instituions. But in that climate it was reasonably well accepted, and to some extent overt racism/homophobia/sexism etc became a matter of shame. It did not go away. It never does. But it did shut up, to some extent. Though not everywhere, of course
Conditions change: gains made are taken for granted: people get fed up with hearing about it when most of what they can see as overtly unfair has been dealt with: subtle stuff is important but it is hard to see and harder to deal with: and it comes closer to home, so most of us would rather avoid it.
So the arguments which got us to that place; the principles which underlay the decisions and the progress get forgotten. Leaving us rather defenceless when the attack comes: as it inevitably does. We find we have to re-invent the wheel, in terms of the argument.
Mostly people are decent and they will shift within limits, most of the time. But sometimes they don't and it is clear to see that we can create really horrible societies from time to time. It is not clear how or why that happens
What I am sure about is that when truly disgusting beliefs are not ashamed to show their face we are not heading in a good direction. And that is because the centre shifts. We are keen on the centre: we talk about a pendulum which "swings too far" and the implication is that the middle ground is always the right place to be. And compromise is a good thing in most circumstance: there is value in centrism. But if extremism is mainstream it shifts that centre: we do not compromise between good and evil and that is the flaw in allowing evil a platform. At least that is how I see it