Neither did I!  Though it was a bit before my time!

And what exactly did the tsunami ruin?  Headlines are like politicians; unbelievable!

I do find some of the theories a bit wild, which does not mean they are wrong.  That something is "unlikely" to happen only means, to nature: give it time!  The physical evidence (what is "Martian geology" anyway?) is there, but theories are a different matter.  How "unlikely" was it for a planet sized object to pass close enough to the earth to rip out the moon but not hit the earth?  Not very, I would guess -- but that is the current (I think) moon formation theory most preferred.  So an asteroid hitting the Martian ocean at just the time it was still liquid, as the dates imply, seems no less likely.  However the story does not explain why the tsunami (or tsunamis?) messed up the ocean.  Certainly on earth the Chicxulub asteroid did not destroy the ocean.  The water just drained back after washing over the land.  Also, speaking of unlikely theories, the one that the Martian ocean formed from giant underground aquifers breaking open seems like bad science fiction that would not even make it in Hollywood!  I don't buy this.  I can't even imagine how it could be possible for enough liquid water to collect in aquifers somewhere on Mars above the level of a very large (though shallow) ocean, stay liquid, and then suddenly burst out and form an ocean!  This leaves the question -- where did all that water come from in the first place?  Last I heard (before this article) the water likely came from a comet, which seems more believable.  No need for giant aquifers bursting!