If memory serves, Ali did not fight for about 3 years - in his prime. He paid a heavy price for standing by his convictions.
From Wikipedia:
“”He was arrested and found guilty on draft evasion charges, stripped of his boxing title, and his boxing license was suspended. He was not imprisoned, but did not fight again for nearly four years while his appeal worked its way up to the U.S. Supreme Court, where it was successful.””
These things are so easy to check so I don’t know why more don’t do it.