Clean up the fix

Author: TomAugspurger

pandas/core/ops.py

@@ -622,11 +622,8 @@ def _is_offset(self, arr_or_obj):
         """ check if obj or all elements of list-like is DateOffset """
         if isinstance(arr_or_obj, ABCDateOffset):
             return True
-        elif (is_datetime64_dtype(arr_or_obj) or
-              is_timedelta64_dtype(arr_or_obj)):
-            # Don't want to check elementwise for Series / array of datetime
-            return False
-        elif is_list_like(arr_or_obj) and len(arr_or_obj):
+        elif (is_list_like(arr_or_obj) and len(arr_or_obj) and
+              is_object_dtype(arr_or_obj)):
             return all(isinstance(x, ABCDateOffset) for x in arr_or_obj)
         return False