I guess I'm missing something with the humor of Leno's comment. Frank Buckles really is the last WWI vet, and he's doing what he can to get a monument recognized for the vets of that war. I for one applaud what he's doing. If you look at what the WWI vets went thru in the early 30's in Anacostia, VA (Cox's Army) it makes a joke in poor taste, least it does IMO. YMMV.
Edit Note: Here's a link to Mr Buckles website.
http://www.frankbuckles.org/