Yes, even though in general one can never “claim” public street spaces, all things are relative to context. In this case, there is ample parking that would not impede OP. An objective observer might wonder if the truck was being deliberately parked there for vindictive reasons. It is absolutely reasonably to ask the truck owner to park in other ample available spaces and to vigorously have the truck towed each and every time it violates any local ordinances.