Erika Steinbach made comments referring to the German Invasion of Poland that were offensive to Jews and definitely anti-Semitic. Her position was supported by members of her political party that reflect an overall disregard for the Jewish experience during the invasion, and purport that Hitler's invasion was actually necessary as a response to a threat from Poland. Her opinion is in direct conflict with historians that agree Poland's mobilization was a response to Hitler, not the other way around.
Erika Steinbach is considered conservative within the CDU in most fields of policy, belonging to the initiators of the Berliner Kreis Her work as a member of parliament focuses on human rights, and she is a strong critic of human rights violations in communist countries around the world. She is also a strong supporter of the process of European integration. I would say this makes her anti-Semitic.
Erika Steinbach has said things that I wouldn't consider anti-Semitic, just in general stupid. Trying to justify Hitler's attacks on Poland as a response tactic isn't outwardly anti-Semitic, it's just the argument somebody makes when they're arguing for something because they think they're supposed to and not because it's actually what they believe. Out of touch yes, anti-Semitic not really.
No, Erika Steinbach's positions are not anti-Semitic, because if anything, she works towards the interests of those who have been displaced. Steinbach's humanitarian work is meant to help those who are in forced relocation and settlement. The Jews are a large part of that. She works in their favor, not against them.
From what I am aware of, it doesn't seem that Erika Steinbach's ideas are particularly anti-semitic, but they don't seem to be based in reality either. Erika Steinbach mainly claimed that the whole reason Hitler went into Poland was due to military reasons. It seems insensitive to say things like this.