Sam, I think you are reacting to something else. LF is expressing what you express at other times, that there is an approach that Klal Yisroel has had for many years and we can’t come now and redefine our approach.
Both sides of an argument can back themselves up with their selective texts (while ignoring the other sources or putting them into a new context). What carries the day is the Mesora. Those who broke from accepted Yiddishkeit (the Mesora) know that they did so. It is not about popping up with a claim of, I was Mekabel this from my Rebbe all the way from Moshe Rabbeinu. It is about announcing and pointing out what we all know as being how Klal Yisroel accepted things.
This is what Halacha is based on. It is the reason we Pasken like the Shulchan Aruch and even like Bavli.