Heat the olive oil in a large saucepan over medium heat.
Add the finely chopped garlic and sauté until fragrant, about 1 minute; do not let it brown.
Stir in the canned tomatoes with their puree, breaking up large pieces with the back of a spoon.
Add the halved Kalamata olives, chopped anchovy fillets, drained capers, dried oregano, and crushed red pepper; stir to combine.
Reduce heat to medium-low and simmer the sauce until slightly thickened, about 8 minutes. Season with salt and freshly ground black pepper to taste.
Meanwhile, bring a large pot of salted water to a boil and cook the spaghetti until al dente according to package directions; drain well and return to the pot.
Add the sauce and chopped parsley to the drained pasta and toss over low heat until the pasta is evenly coated, about 3 minutes.
Serve immediately with grated Parmesan cheese on the side.