I'm a big believer that people should not be held responsible for the sins of others. Also, teenagers shouldn't have their reputations permanently damaged for ignorant stuff they say on account of being teenagers.
That said, however...
Parents are a child's No. 1 influence. When a teen regularly tweets astoundingly bigoted messages for the whole world to see, one (or both) of two things is happening:
1) The child is learning such behavior from their parents, and/or
2) The parents aren't giving sufficient oversight to the child's activities.
The second point would seem especially relevant for someone who holds high elected office, as a member of a party trying to shake a reputation of prejudice. Short of that, surely Joe Heck wants to be a decent parent at least. One would hope.
Yes, it's no given that offspring reflect the political or social views of their parents, especially at 16. But in my experience, every racist I've ever met had parents who held similar views.
Given how little I know about Joe Heck, I can't say for sure what he holds in his heart. But if how his son talks is any indicator, his first impression isn't too good. And this doesn't help:
'I am extremely disappointed in my son’s use of the offensive and inappropriate language on twitter: that type of language has never been permitted in our home,' Heck's father said in a statement to Buzzfeed.
What kind of apology is that? He might as well have said, "I am extremely disappointed in my son's use of bad words when expressing his hate for blacks and women. I would prefer he use more polite words when tweeting that hate."
The words aren't the problem; the hate behind them is.