「UNIFIED REICH」は初耳だったので軽く調べてみましたが、BBCもCNNも仰る通りドイツの第三帝国を想起させると書いていますね。
https://www.bbc.com/news/articles/c7228wlpe0ko
www.bbc.com
One mentioned the “creation of a unified Reich”, a term now often associated with Nazi Germany. The text appeared to draw on a historical reference to Germany’s unification into a single empire, or Reich, in 1871.
https://edition.cnn.com/2024/05/24/media/trump-unified-reich/index.html
The video, posted and subsequently removed by the Trump campaign earlier this week, included imagined headlines that newspapers might run if former President Donald Trump is reelected. Among them: “What’s next for America,” under which the fictional article displays language that many associate with Nazi Germany, including the phrase, “creation of a unified Reich.”
AP通信はもう少し踏み込んでいて、件の動画は「第一次世界大戦に言及している」としています。
The headline appears among messages flashing across the screen such as “Trump wins!!” and “Economy booms!” Other headlines appear to be references to World War I. The word “Reich” is often largely associated with Nazi Germany’s Third Reich, though the references in the video Trump shared appear to be a reference to the formation of the modern pan-German nation, unifying smaller states into a single Reich, or empire, in 1871.
BBCとCNNが捉える第三帝国説であろうと、AP通信の捉える1871年のドイツ統一にかこつけたものであるにせよ、どちらも「景気が良くないお話」には違いないでしょう。
質問者さんはUNIFIED REICHに注目していますが、批判されたとすればやはり全体の問題でしょう。たとえば以下は上記BBC記事ですが、様々な人物への誹謗中傷がトランプ元大統領の動画にあったと記載されています。どこをとっても批判されるものでしょうし、単語一つの問題ではないでしょう。
Some of the videos and memes created by the team – which consists of around two dozen accounts – are crude and insulting parodies of music videos or other content.
Some of their clips have depicted Nikki Haley as a prostitute, Ron DeSantis’s wife Casey DeSantis as a pornographic actress, and President Biden as a paedophile. Others allude to conspiracy theories about the “deep state”, federal agents and vaccines.
上記記事群が事実なら「なにが問題か」というより、「なにが問題でないか」を考えなければいけません。「なにが原因で批判されたのでしょう」と聞かれば、おそらく全部と答えざるを得ません。