The Gemara says ,”Lama Li Kra, Sevara He?” Judaism is a rational religion.
Lol, thanks for proving my point.
למה לי קרא means that you only need a posuk to prove something illogical, i.e., NOT everything in Yiddishkeit is rational!
למה לי קרא is saying, why do we need Torah for things that could be understood without Torah!
The discussion in the Gemara Taanis is the FLIPSIDE of למה לי קרא סברא הוא: Rav Yitzchak acknowledged that according to סברא it would be ridiculous to say that Yaakov is alive, but he responds מקרא אני דורש – it may not be logical, but that’s what the Torah says!
He only needs to bring a posuk because it’s not logical! If this was rational, Rav Nachman could have responded to the hekesh למה לי קרא סבתא הוא!