There are certainly actual examples of it, but a lot of it is propaganda, particularly when it's supposedly communists doing it.
The reason why people would pick that particular bit of propaganda here has to do with fascism (or more broadly, beliefs in your supremacy over others), which faces a pretty serious practical contradiction - actually winning a war typically requires you to take things seriously and properly evaluate your enemy's capabilities... except fascists are fundamentally detached from reality for ideological reasons. There was the classic line from Eco's essay that "Fascist governments are condemned to lose wars because they are constitutionally incapable of objectively evaluating the force of the enemy". Why would you take your enemy seriously and prepare for the fight when you believe them to be literally beneath you, as a living being?
However, some of the smarter fascists realize this, and try to address it - and one of the ways they do it is with the idea of the enemy being a great horde. This way, you can still maintain the key fascist belief - in a one-on-one battle, obviously our guy would mop the floor, but the problem is that those other guys... there's just too many of them. And they fight dirty - being... well, inferior, they obviously lack positive values such as honor, so they'll just send their guys at us in waves, with a callous disregard for their lives (I remember there being some US general during Vietnam, who was questioned about whether the incredibly high casualties from bombardment might be somewhat counterproductive and driving people towards the Viet Cong... and he basically said "you see, there orientals simply have different values about life and death, so they don't really care about their loved ones dying as much as we would". I think it may have been the RevLeft episode on Vietnam where I heard that one, don't remember).
So, that way, you get to still take your enemies as a serious threat, but without having to question your supposed superiority.
There are certainly actual examples of it, but a lot of it is propaganda, particularly when it's supposedly communists doing it.
The reason why people would pick that particular bit of propaganda here has to do with fascism (or more broadly, beliefs in your supremacy over others), which faces a pretty serious practical contradiction - actually winning a war typically requires you to take things seriously and properly evaluate your enemy's capabilities... except fascists are fundamentally detached from reality for ideological reasons. There was the classic line from Eco's essay that "Fascist governments are condemned to lose wars because they are constitutionally incapable of objectively evaluating the force of the enemy". Why would you take your enemy seriously and prepare for the fight when you believe them to be literally beneath you, as a living being?
However, some of the smarter fascists realize this, and try to address it - and one of the ways they do it is with the idea of the enemy being a great horde. This way, you can still maintain the key fascist belief - in a one-on-one battle, obviously our guy would mop the floor, but the problem is that those other guys... there's just too many of them. And they fight dirty - being... well, inferior, they obviously lack positive values such as honor, so they'll just send their guys at us in waves, with a callous disregard for their lives (I remember there being some US general during Vietnam, who was questioned about whether the incredibly high casualties from bombardment might be somewhat counterproductive and driving people towards the Viet Cong... and he basically said "you see, there orientals simply have different values about life and death, so they don't really care about their loved ones dying as much as we would". I think it may have been the RevLeft episode on Vietnam where I heard that one, don't remember).
So, that way, you get to still take your enemies as a serious threat, but without having to question your supposed superiority.