I do not recall a historic event that this is done with the aim of persecuting Buddhism
Probably you missed, or was inattentive to, all of your classes about the last two millennia of Asian History.
Buddhists and Buddhism have been persecuted by Hindus in India since the 2nd century CE; by Zoroastrians in Persia in the 3rd century CE; by Manichaean Hephtalite Huns in Central Asia and Northwestern India in the 5th and 6th centuries CE; by different Chinese Emperors in China in the 6th, 9th, and 10th centuries CE; by king Landarma in Tibet in the 9th century CE; by British and French colonialists in Sri Lanka and Vietnam in the previous two centuries; by Chinese Muslim warlords such as Bai Chongxi and Ma Bufang, and by Communist Cultural Revolutionaries, in the last century; by Christians in South Korea nowadays under our nose; and, of course by Muslims in India, Central Asia and Indonesia, starting in the 12th century or before, who razed Mahabodhi, Nalanda, Vikramashila, Odantapuri, and almost every trace of Buddhist culture, society, and civilization in such countries and regions.
To put it mildly, yours is just an uninformed, irresponsible statement.
And as to the US nuclear and carpet bombings decimating millions of Buddhists and razing countless Buddhist shrines in Japan, Korea, Vietnam, Laos, and Cambodjia, while not officially self-described as an attempt to exterminate Buddhism, worked precisely as such, which is hardly a coincidence, considering that such massacres and razing of Buddhist temples where the brainchildren of synagogue-going Jews such as Bernard Baruch, Henry Kissinger, and others.
Nazism of course is evil all by itself.
The funny thing here is that every single evil element in “Nazism”, such as the belief in racial superiority and inherent land rights, find their roots in Judaism. Meanwhile, German National Socialists implemented many beneficial laws protecting workers, women, children, and animals, which belies widespread stereotypes spread by war hate propaganda.
Also atrocious Islamic State practices, such as gruesome death punishment by stoning and decapitation, massacring of women and children, taking young girls as sexual slaves, and so forth, find their roots not in Hitler's
Mein Kampf, but in the Jewish Old Testament, the gruesome manual of terrorism also accepted and venerated by Christians and Muslims.
Therefore, one might want to get rid of propaganda and ask oneself what is “all evil by itself”.