It's WW1 propaganda, which is blamed on nationalism.

Just explaining, not saying it's right: 'nationalism' is regarded as denigrating other peoples in a mean way or unironically hating them (unless it's Germans whom it's OK to hate).

Europeans also have no idea what America is like (same as the other way around), they tend to think that America is very 'racist', and that it has 0 social welfare systems.

It's WW1 propaganda.