I don't believe that a horse and rider properly prepared to ride to a "Top Ten" finish is inherently a dangerous thing. I don't think a properly prepared horse (and all that THAT means) even has trouble top-tenning 50's or 100's.
Now, there are riders, even with properly prepared horses, who choose to ride more slowly and get to enjoy the trail, and all that THAT means, for longer periods out there.
That's wonderful. I'm one of those folks, more often than not.
But, if a rider actually experiences FEAR when riding to a Top Ten finish, perhaps it might be that that rider does not have the right horse, has not prepared properly for the endurance challenges out there, needs more education, and so on.
I think if I could go down the list and discount the selection, the preparation, etc., as being causal regarding the belief that Top Tenning rides kills horses, maybe then, I'd realize that going slow is something I CHOOSE to do, but don't HAVE to do.
But, by no means, would I ever consider calumniating on Top Ten riders.
A stupid horseman deserves all the recognition he gets, though.