There's a saying in a self help group I am familiar with: "We do not regret the past, nor do we wish to shut the door on it." We can't change what has happened to us or the world in the past. But what we can do is focus on making the future better.
To be living in the past with regrets or something of the like would be to renounce the present and the potential of the future. People who live in the past would be regretting things they have done wrong or opportunities they miss, but people who look to the future can visualize what they want and achieve it are working towards something greater.
I do think it is important to renounce the past in some ways, and not to dwell on things that happened; dwelling on the past can destroy a person. But if you are able bodied, there is a chance for you to seize the future every day of your life.
I believe it is better to seize the future than to renounce the past. If a government or person is responsible for an evil act in the past, it is important to renounce that deed. However, it isn't something that can be changed. The only way to be a positive force for good is to seize the future, and be the best that you can be. If you are mindful of the past, you can also use that experience to guide you in the future.
I feel that it is better to seize the future than to renounce the past. You cannot change what happened in the past, you can only learn from this. The past is not a direct indicator of what will happen in the future, and the only thing you can do to secure a better tomorrow is to seize that opporutnity.
We must criticize what has transpired to better comprehend and analyze a more productive future. We must look at the past, depending on the subject, and objectively find what causes what and to what extent. If it is terribly destructive in a negative way then we can mend our ways to better behave in the present thus making the most productive future possible. Greater emphasis should be made of the present because the future doesn't get here early enough and the past is too late.