His Royal Highness:
“For decades before the current B.P. and Flatbush eiruven were established (in the early 2000’s), there was a Flatbush Eiruv maintained by the Young Israel crowd. Why was that universally rejected by the heimishe (Litvish/Chasidish) community? Why was that eiruv worse than the current eiruv?”
Because of the huge machlokas that ensued. The current eruv is based on the fact that Brooklyn is encompassed by mechitzos. The current eruvin are built with many more chumros. They are also omed merubeh eruvin.