Ubiquitin,
1. They do not say “all his pesakim” but “his pesakim”. Apparently they are only referring to this one case.
2. Only four gedolim signed. Rav Zolti also disagreed in print. I do not know of any other gadol (Rav Avraham Shapira, Rav Mordechai Eliahu, Rav Nebentzahl, etc.) who disparaged Rav Goren.
3. For a balanced discussion google “Rabbi Bleich the Langer case” and you will get a link to his article in “Contemporary Halachic Problems”.
4. I repeat my question. What about the recent wave of Charieidi dayanim invalkidating conversions?