I dunno. I don't have kids and I'm not especially good with them, so maybe I'm missing something here, but I think I would kind of look at those little girls like, . I would wonder if they were already drama queens or used to getting whatever they wanted just by carrying on.
If they were 15 I'd say drama queens. If they were 12 year old girls, I'd say that there was probably complex machinations going on behind the scenes to exclude certain girls and make sure they knew they were excluded - so drama, but not necessarily coming from the uninvited girl.
But for 3 or 4 year olds? That I'd consider totally normal for their development stage.
Even for adults, being the only one of a group of people not invited to a fun thing you'd like to be invited to, and listening to everyone else chatter about how much fun it's going to be (or was) can be hurtful. But by the time you're an adult, you've learned to suppress your reaction, and rationalize ("I didn't really want to go anyways/they're a bunch of losers/I didn't like them in the first place").
For a four year old, kids that age tend to be really, really honest about their emotions and not at all good at hiding them. That makes things like tact, social white lies and pretending to like someone for external social reasons incredibly difficult to explain. They can be starting to learn it, but they won't have gotten really far at this point.