The claim of "ordinary" is subjective not objective.
It is used in two separate contexts - one as meaning "rare". How rare does rare have to be? the other as meaning "opposing base assumptions of what is normal present world view" The second is entirely subjective.
Rare events make classification of ordinary or extraordinary useless.
The collapse of comet ison and break up happened only once.
Did that mean it is so rare it did not happen?
Even lack of evidence does not invalidate a phenomena: it just makes it harder to make defintive statements. In a world before cameras and high power telescopes did the lack of evidence mean that comet break up did not happen? Are ancient witness statements enough?
Stuff happens or it does not.
How "common place" it is, is of no consequence. The fact something is commonplace does not mean it happened in any particular instance.
All truth must be subject to the same standard. Ask a court.
Of course the ability to model it, requires either repeating or repeatable phenomena or things which extrapolate from present model. That is part of why science is limited in what it can model.
On rarity - If we are to believe dawkins type evolutionists the creation of life happened once by accident. It is truly "extraordinary" that a self evolving and replicating 10000 chemical factory complete with software, just happened without a designer, and there is no evidence at all it ever happened. Nobody saw it. There is no visible "production line" of large scale intermediates to the first minimum cell as we know it. No record there ever were such intermediates. A complete void of evidence.
Yet it is considered "ordinary", as is consistent with atheist faith and world view, and so assumed to be true. The difference between theists and non theists is the acceptance of what part of what is believed to be true is just belief.
You produce evidence of your claimed magic pixie.
Science is a game that has rules. Sagans statement broke the rules. In scientific context. Your magic pixie is subject to the same standard of proof as any other claims.
Would you have any problem in believing that I am married? Why would you think I would lie about something like that? And I've no reason to doubt that you are. It's in your details. Just our say so is good enough to accept those facts. But if I said I had a magic pixie in my garden that grants wishes, then something tells me you'd have some doubts about that.
One is an ordinary claim that needs nothing more than ordinary evidence. And one is an extraordinary claim that would need a great deal more.