Isn't that what the article says
.... "The finding would be significant because so far no one has been able to prove that aquatic dinosaurs existed, Joanna Wright, assistant professor of geology at the University of Colorado-Denver, said Monday.
No. There are no aquatic dogs either, but you apparently think that should mean that dogs don't swim at all. Despite the fact that your own dog takes a dip every now and then.
If you just consider logic.... which is more logical... that it's foot prints from a big bird that existed long ago...
Well, since you're ignoring the fact that we know dinosaurs existed 165 million years ago, and there's absolutely no evidence of birds back then, I'd say that your claim to the "more logical" position is shaky, at best.