Ones that have been watched closely because of high mortality in birds? Spread globally? And jumped species to different mammals?

Dismissing H5N1 out of hand is like saying we shouldn't be concerned if Ebola Reston showed up worldwide, in multiple species, because it's not known to infect humans.

H5N1 already has a lot of characteristics that would make it very concerning if it also became human to human transmissible. Ergo, we should take it seriously.