In western world at present it could be argued that the biggest threat is the massive increase in inequality. It's a fact that the rich are getting richer and the poor are getting poorer.
It may be assumed that increasing inequality leads to increasing support for left wing ideas and that increasing equality - trickle down meaning that the poor get richer - leads to support of right wing ideas.
Actually, the reverse is the case. Increasing economic inequality leads to increased support for right wing ideology. The previous high point in inequality was in the 1930s and we all know the ideological consequence.
The analogy of rats fighting in a cage whilst ignoring the experimentor outside the cage is apt.
At its core right wing ideology is divisive, it pits white against black, male against female, straight against gay, indigenous against immigrant, able bodied against disabled, gentile against Jew etc. But not poor against rich. As a supposed explanation for inequality that leaves the rich and powerful untouched if not increasing wealth and power.
So poor people get in a froth about immigrants stealing jobs, houses, benefits - remember when it was about teenage women getting pregnant for a council house? - so much so they are willing to try and burn them alive - but think they are justified and not like the people influenced by right wing ideology that preceded them.
No one but the influenced care about definitions. 'I am not a fascist'. Methinks you protest too much.