I AM SAYING THIS B’RABIM BECAUSE I KNOW IT IS TRUE.
AND BECAUSE I’M TYPING IT IN CAPITAL LETTERS IT’S EVEN TRUER!
Seriously, however, if you hold Rav Belsky to be the Gadol Hador, and his opinion is not to use the eruv, then by all means don’t use it. But not everyone holds that Rav Belsky is the gadol hador and not everyone uses Rav Belsky as their personal rav. For all his greatness, he is NOT Moshe Rabbeinu (i.e. the undisputed leader of the entire generation) — despite your insistence that he is.
Stop playing the “my gadol is bigger than your gadol” game.
The Wolf