It's too late now for me to quit. I might as well keep on smoking. They may think they are forgiving themselves, but the reality is they are only making excuses. There's a big difference between making excuses and truly forgiving. An excuse denies the reality of a problem.
Forgiveness acknowledges a problem, yet moves beyond the problem.
To forgive your own smoking, you must admit to yourself that you have a problem that began in the past. Acknowledge the past, but also acknowledge that the past is over and can never be changed. What's done is done, now you must move on. Forgive yourself for starting to smoke. Acknowledge that this happened and that it may have been wrong, but what's done is done.