Whether or not you personally are a racist is irrelevant. The issue is whether Zionism is an ideology that, in practice, has discriminated against and dispossessed Palestinians for decades, and continues to do so, and the answer to that question is: yes!
Hence the racism label.
Zionism does not mean different things to different people as the Green Party suggest. It is the belief in the right of national self determination of the Jewish people in the State of Israel. That is it.
I am a Zionist. And now, according to the UK Green Party, I am a racist.