Very sad. I’m sure your grandfather was traumatised by that, but I’ll bet he still loved America. You may be able to find out what happened to him on Ancestry.com.
My point would be that immigration laws were very strict, so much so that the migrants would not argue over their decisions, lest they be disallowed also. It affected my family, and the story was told in a way that was sad, but not mad at the country. They were glad to be here, as the reason for coming here was to avoid another draft. It seems that one of the interminable wars was coming, and they drafted at age 12 once the casualties started piling up. My great great grandma said NO MORE.