In Uttara-kāṇḍa of Vālmīki Rāmāyaṇa, we see Vālmīki narrate the story of Śambūka.
Questions:
Why did Rāma kill Śambūka? Is it because Śambūka was a śūdra or is it because he was doing tapasyaTapasya for the wrong reasons? Were śūdras not allowed to become a ṛṣi?
And is Rāma justified in killing him without a dialogue or a second chance? Why didn't he just imprison him? What was the need to eliminate Śambūka altogether?
PS. This question is similar to: Why did Lord Rama give a second chance to Ravana, but not to Vali?