Specifically, the US considers anyone who is male and "of fighting age" not a civilian - and the "male" part is often optional.
This does somehow still result in a lower ratio of dead civilians than when applying the same definitions to Russia or Israel. This shouldn't be seen as a way to excuse the behavior of the US but rather as a way to recontextualize the actions of the latter two, whether you support or oppose their military operations.
I don't think it helps anyone to separate what israel does from what USA does. Everything that israel does is authorized and aided by the USA. It'd all stop the very second the USA told them to stop.
This does somehow still result in a lower ratio of dead civilians than when applying the same definitions to Russia or Israel. This shouldn't be seen as a way to excuse the behavior of the US but rather as a way to recontextualize the actions of the latter two, whether you support or oppose their military operations.