Listen, your mom's math teacher didn't make your mom give up her dream to be a teacher, your dad's relative didn't make him stop taking photos, and your parents didn't make you suffer from a lack of self-esteem.
The three of you made your choices, and they led you to where you are now. You may consider that what your parents have done has strongly influenced you in your choices, but they did not force you to make the choices you made. If you insist that indeed they did so, that you are a powerless victim of their choices, then what you are doing is blaming them. Let's call a spade a spade.
If you are suckling no blame for them, then what good outcome could you hope for by "making them aware" that the choices they made were wrong? Just because you don't like their choices, or that you would prefer they had made others, doesn't make them wrong, any more than you are "wrong" for having had low self-esteem. It's not their fault, and it's not your fault.
You are certainly free (and wise) to say "no, thanks" to someone who is trying to give you something you don't want -- like criticism or nagging or crankiness. But when you turn around and tell them how wrong they are, how wrong they've been, and how you are just the person to enlighten them about making better choices in their lives, then you become exactly what you are trying to shrug off -- a criticiser, a nag, and an old crank.
It's not about negative input; it's about negative uptake. Do you want to be a person who generates negativity in the lives of these people whom you care about so deeply (disguising it as "making them more aware"), or do you want to be a person who generates people (including yourself) feeling good on purpose?