Let me digress here a bit. There are two ways to assess risk. One is the probably that a bad event will occur. That is, how likely are you to get a bad outcome if you take the risk. The other is the severity of the outcome if the bad event occurs. Thus, if you know there are bad skittles in the bowl, but they just taste bad and you can spit it out if you get one, you'll likely go ahead and have some skittles. On the other hand, if you know that some of the skittles are so poisonous that one bite is deadly, you'll not eat any of them.
So Trump Jr. has been attacked for using this analogy, for suggesting that people could end up dead, the most severe outcome. Some say the analogy's roots are in Nazi Germany. Others relate it to white supremacy. Jr. is mostly shrugging off the criticism.
I'm no Trump or Trump Jr. fan, but I think this criticism is overblown and off base. It's the presidential campaign silly season, so supporters of one side will attack the other at any opportunity. Happens all the time, and I think it undermines the credibility of the attacker. If you make a weak, exaggerated attack on one issue, it just makes all your attacks look weak and silly, even the valid ones.
Muhammad Ali used a similar metaphor (or, maybe this is an analogy). He said that not all white people are racist, but he was basically going to act like they are, just to be safe. In his case, he likened white people to rattlesnakes.
There are many white people who mean right and in their hearts wanna do right. If 10,000 snakes were coming down that aisle now, and I had a door that I could shut, and in that 10,000, 1,000 meant right, 1,000 rattlesnakes didn’t want to bite me, I knew they were good... Should I let all these rattlesnakes come down, hoping that that thousand get together and form a shield? Or should I just close the door and stay safe?