From the little we know about the LBT 11 plot, I could very well imagine that Littlefoot doesn't see the fatal results about that lie he utters. I mean, it seems like the fruits of one tree were lost and Littlefoot doesn't admit that it was him who acidentaly knocked down the blossoms.
It is not like there is only one tree in the Great Valley, and even in case it was the only one with these "tree sweets", how could Littlefoot expect the grownups to get in such a "get Frankenstein" kind of frenzy?
I mean, come on grownups, this is only one tree!
I could imagine that Littlefoot did think that way, while I'm sure that he didn't like a demagogue set everyone against the Tinysaurs.