If we were still in the 1800s, sure. But now? Dollars to donuts, I doubt it.

"Most German immigrants all Americanized their names "
Re-read that. Besides being poorly written, it's also inaccurate. There were period where anglicization was more common, but rarely anywhere near "all". Frankly, it was in cases often for practicality (because Americans can't pronounce anything "weird" which is why for Portuguese, Martin (Mar-teen) became Martin (Mahr-tin), Silveira became Silver, and almost any other "ei" centered surname (Pereira, Ferreira, etc) got given a soft-E instead of a long-A sound. For German, the double-S letter (ß) was dealt away with wholesale, and pronunciations often stayed intact while spelling shifted for practicality (e.g. Bauer became Bower) but hardly hid anything from view.

Also, anglicizing of names is common in the US and England, but historically it was often forced rather than chosen (that doesn't change the anti-immigrant underpinning, but does change the method).

This topic is a lot more complex than you rebutted., and it's one I have a big pet interest in, but I suspect that's not the point you were trying to make (albeit very clumsily). My first sentence still stands. And as for "Americans were notoriously anti-Irish, anti-Italian, anti-German, anti-anything" you've just described almost every spot of humanity on the planet (really, find me a single society anywhere in history, anywhere on the planet that at one time or all didn't have or contrive a convenient "other" to lambaste). But what do I know, I'm just a misanthrope on the internet.