They are actually designated as a terrorist organization by a very large number of countries. Almost every country in that region does, and around the world.

Also, they do all sorts of things. The big one was contributing to the deaths many people in syria. I think thats more than enough for countries to call them a terrorist organization as they do now.

Its pretty horrible. You can look it up here: https://en.wikipedia.org/wiki/Hezbollah_involvement_in_the_S...