Bring a large pot of salted water to a boil and cook the elbow macaroni according to package directions until al dente; drain and rinse under cold water to stop cooking, then set aside to cool.
In a large mixing bowl, whisk together the mayonnaise, yellow mustard, dill pickle juice, sugar, kosher salt, and black pepper until smooth and well combined.
Add the cooled macaroni to the dressing, then fold in the diced red bell pepper, diced red onion, diced celery, and finely diced dill pickles until everything is evenly coated.
Taste and adjust seasoning with additional salt and pepper if needed.
Garnish with minced parsley if desired and chill before serving for best flavor.
