Askan means baalabos doing klal work, not a gadol. Their agendas and actions are not as pure as those from a gadol, who by definition is a tremendous baal middos (Rav Shach told this to Shlomo Lorincz, and Rabbeinu yonah on Pirkei Avos confirms this). When we say daas chachamim hepech midaas baalabatim, we don’t just mean the “left-wing” baalabatim. The chazon Ish ZT”L referred to neturei karta as “Jews from before Mattan torah”, even though their views on Zionism were similar. However, their actions based on those views were so divergent that The chazon Ish ZT”L had to clarify. The Chazon Ish fought Zionism, but he wasn’t about fighting and hatred. Neturei karta, on the other hand, was about fighting, but they happened to be fighting zionism. That is how they could descend into hugging Jew-haters, while the Chazon Ish ZT”L was known for his
Many askanim have personal agendas, or are fooled into believing that all is muttar when you can wrap yourself in the cloak of “leshem shomayim”. One gadol once described this difference as the difference between a house cat and a housewife in terms of mice. both will kill mice, but one would rather the mouse not be there, while the other wants the mouse to be there in order to kill it. As you never know with askanim, it pays to speak to a rebbe for guidance. Finally, Rav Shach ZT”L publicly went against Maarava and Michlala, but told talmidei chachamim working in them to stay. So clearly you can’t go based on kol korehs.
Gedolim are fooled a lot less than you or me, but we Yidden don’t believe Daas Torah means papal infallibility. It means their viewpoint on issues stems from the Torah, not from a personal bias or agenda. Rav Shach helped found the Shas party, and later withdrew his support when they joined with Shulamit Aloni.