Why do certain people feel this is ok
Because they are selfish pricks who believe it is their right to do whatever they want and it is their right never to experience adversity in life.
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I felt that I had no right to do anything
Poor excuse, and it is just an excuse. You saw something that was wrong, you knew it was wrong but didn't have the fortitude to do what was right. Instead you rationalize your way out of it.
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You have every right to speak up when you see something wrong, in fact you have an obligation to do so. You failed miserably.