The number of Germans that had problems with Jews increased in proportion to media based propaganda in the 1920s and 1930s, just as is the case with the number of non-muslims that have problems with muslims in the current era.
When media politics targetting Jews or Muslims or whatever the latest emotional hot-button is, intensifies, the number of people who might identify or be identified as 'anti-Jew' or 'anti-Muslim' rises. In other words, this 'count' is inductively increased by the ambient rhetoric. Such increases are ambient emotional trend induced. That is, they are epigenetically induced genetic expression. They do not arise spontaneously from the individuals themselves; i.e. the individuals are stirred up by ambient emotional surges stirred by politicians whose voices are amplified by the media.
To jump to the conclusion that 'anti-semitism' is a 'movement' that is 'undergoing growth is to falsely identify the source of the growth; i.e. the growth is epigenetically induced, not genetically driven. In fact, such growth waxes in wanes as politicians and media effects stir it up.
Journalists who use terms like 'alt-right' or 'far right' as if they refer to real physical movements are deceiving the public. The population of 'alt-rightists' is inductively grown and peaked on voting day because of scary political rhetoric that is fanned and fuelled by the media, same as with the population of 'BREXITists'. These are not 'movements' as in 'movements in themselves' with internally sourced, they are epigenetically induced on a transient basis. The more scary rhetoric in the media, the more the population of 'alt-rightists' rises. This is not 'net growth'. There is only the illusion of growth; i.e. those within a single collective that just yesterday were not identified as 'alt-rightists' or 'anti-semites' and who, tomorrow, will once again not be identified as 'alt-rightists' or 'anti-semites', are momentarily identified as 'alt-rightists' or 'anti-semites'.
This is the same illusion as in defining the growth of a hurricane. If we divide the surface of the earth into say 100,000 areal cells and measure the wind velocities within the cells [stirred by variations in solar irradiance and ocean currents], if the solar and oceanic influences intensify in such a manner that the number of cells with winds of hurricane velocity 'grow' from 1 to 3 to 5 to 11, ... there is no 'movement there' that is 'growing', there is a 'form' that the observer sees as 'growing'. the observer is just changing the category he is assigning to the same (essentially) things. The growth lies in his changing categorizing of the same things.
The Guardian, like media instruments in general, contributes to this deception that the 'alt-right' movement is a 'real thing' by speaking as if it were by using the following sort of 'semantic trickery' [the reason why Robert Alton Wilson and others use 'E-prime', English with 'isness' removed].
"People within the movement"
"Regarding the breadth of the movement",
"a movement that is defined by an ideology of ethnic purity and encompassing neo-Nazis",
"individuals associated with the movement"
"a far-right movement".
it is not a movement but the process of varying the imposing of a subjectively and incompletely defined category on the same things.