Whats the source for Lubavitchers to make a bracha when lighting the menorah in the Park or at any public lighting ceremony not done at a place of residence?
If you want to bring a source from the fact we light in shul, the rishonim say that the minhag was started because there were people who lived/slept in the shul. Even if you want to say it was still done in shul because there was more persumei nisa there, we find that it is a very specific minhag to light in shul with specific rules as to where in shul and what direction it faces and so on and so forth. Where do we find the concept of lighting just for persumei nisa without any minhag for it?