If you read the replies to Trump's tweet on Twitter, half of them are whining about Kathy Griffin. She's their favorite example of how Twitter has a liberal bias today. Maybe you coincidentally picked the same example as them.
I listen to both sides, and I don't pay attention to what people say on twitter too much (it's the not "real" world). again, I'm not saying this tweet is equal to what trump said, it's clearly not --- But if someone had harmed or killed one of these kids because of this dox, I'm not sure your objections would stand. And with 2.1M followers, that is in realm of possibilities
