Littlefoot had just led them into more badlands.  How were they to know he was going the right way or not?

So you say Cera was worse than Littlefoot?  How about when he set Ducky up to be bait for Sharptooth?  Instead of taking on the role himself, he jeopardized someone else's life.  They both made their fair share of mistakes.  Everyone makes mistakes, even dumb mistakes.  Nobody got hurt or worse in the end, so I wouldn't be saying anyone was "worse" than the other.