Come on. People not eating products certified by the Belz Machzikei Hadas certification in Israel has nothing to do with politics between different chassidish sects or opposition to the chassidus. Most people I know from the yeshiva world are generally perfectly happy eating from chassidishe hashgachos, and hold highly of the Belz chassidus and Rebbe. They happen to have specific concerns about the Hashgacha which makes them hesitant to rely on it. It has nothing to do with their political leanings and philosophical antipathies.