You're technically right (multi-core CPUs can do true parallelism), but you were downvoted probably because your point was obvious (to the people who downvoted

You're technically right (multi-core CPUs can do true parallelism), but you were downvoted probably because your point was obvious (to the people who downvoted you). A multi-core CPU is basically multiple CPUs. The details (multicores share the same die, use the same caches, etc.) are mostly irrelevant here.