In Korea, there are many outdoor exercise machines in public places. This kind of machine is a particularly common one. Is this effectove as a post-run hamstring stretch? It feels good, but it is quite a fast, short-lived motion, unlike most other stretches such as a toe touch. Considering this is post run, maybe my muscles can take it as they've been warmed up.
The machine you show is actually another type of elliptical trainer typically meant for light exercise or cardio work. I would suggest you look at performing some active stretching following a specific program for the hamstrings. For example, following a program designed for the target muscle. You may also want to search the ExRx site for stretches.