Wiki - The paradox of tolerance states that if a society is tolerant without limit, its ability to be tolerant is eventually ceased or destroyed by the intolerant. Karl Popper described it as the seemingly self-contradictory idea that in order to maintain a tolerant society, the society must retain the right to be intolerant of intolerance.
Yes, the person who is against oppression is the oppressor. You couldn’t think your way out of a wet paper bag. And the word is ‘impose’ pick up a dictionary, work your way up to university level cognition from there.