That’s what people say now, however I suspect that’s a KMT constructed sentiment.
Early Han Chinese civilians were very oppressive to the flatland tribes, but had little interaction with those who have official Aboriginal status today. Most of them had interactions with the Qing government. For example, Pangcah (Amis) men of Makotaay, Dafdaf villages were massacred by the Qing government after Qing soldiers failed to gain access through their villages. Qing general Wu Guangliang then set up a feast and invited the men over for a truce, then killed them all afterwards. However, those events had little to do with Han civilians.
The only existing tribes that would have a beef with early Han immigrants are the Ita Thao, Saisiyat and Altayal where Han civilians established militias to contain them. However, they mostly had interactions with the Hakka and not the Holo.
There’s little evidence that those with Aboriginal status today had much conflict with Early Immigrants during the Japanese era either, and after the KMT took over Taiwan, most Taiwanese rebellions saw Early Immigrants working together with the Aboriginals.
During the 228 incident, Tsou leaders Uyongʉ’e Yatauyungana and Yapasuyongʉ Yulunana formed Aboriginal militias that cooperated with Han militias to maintain peace in Jiayi city, and blockade Shuishang airport. They were both killed by the KMT during the subsequent White Terror era.
Even aboriginals who had nothing to do with armed militias during 228 were killed by the KMT during the White Terror era. The most famous is Altayal Medical Doctor Losing Watan, who was a member in the Provincial parliament. Others like Truku leader Walis Wumi who was adamantly against Japanese rule and celebrated the arrival of KMT was also killed by the KMT.
During the 1970 Taiyuan prison rebellion, political prisoners, mostly Holo early Han immigrants, also coordinated with local Aboriginals in a planned armed uprising against the KMT.
en.wikipedia.org/wiki/Taiyuan_Incident
After the establishment of the KMT dictatorship all the way till today, any discrimination or oppression suffered by the Aboriginal people is either caused by the government or all Han ethnicities as a whole. If Aboriginals today dislike ethnic Han buying their land, making fun of their names, disrespecting their traditions, it’s on all 3 Han ethnicities. I am not saying that a certain Han ethnic group didn’t practice ethnic discrimination. I am saying all of them were and still are equally responsible for the hardship that the Aboriginal people suffered due to Chinese colonialism.
So why the particular animosity towards Holo? There’s no explanation at least from a historical context. Some Aboriginal youth suggested during the last election cycle that since there are more interactions with the Hakka and Late Immigrants (serving as overlords), Hakka and Late Immigrant opinions of Holo rubbed off on newer generations of Aboriginals.