You didn't bother to finish the quote.  Trump ended it by saying "he was really angry that he saw what was happening with regard to the Civil War."And as has been pointed out, Jackson had been dead 16 years before Fort Sumter.

This is why people are bemoaning his ignorance.  And let's not forget that Jackson supported slavery and passed the Indian Removal Act, making hm a questionable role model for a modern day leader.