Not attacking another candidates character will be good for him, but doing that won't entice Mrs. Clinton's to join a friendly, sensible conversation. They're not interested in a conversation.
I've tried to converse with Hillary Clinton's supporters online and offline. I've read and heard praises of her in the media. I've heard other celebrities talk about her. Here's what I've discerned.
They think she's the greatest person who ever lived and believe everybody is supposed to feel the same way. They believe she has never done and can never do anything wrong and that any time she does wrong it must be a lie the Republican Party started. When she began giving public speeches earlier this year, she talked a whole lot of nothing and her audiences cheered. They don't care that she flip-flops on important issues. They don't care if she lies about herself (such as her mythical attempts to stop global warming), others (Mr. Sanders), the law (whistleblower protections) and recent history (anti-gay laws, Colombia). They're willing to believe every lie she tells.
They seem to have incorrect assumptions about what she stands for. They think she won't start unnecessary wars. They think she wants to stop climate change. As a Senator and a diplomat, she proved otherwise. And they don't care that she consistently supported more surveillance, even to the point of demanding the DNA of friendly foreign diplomats and heads of state (see the diplomatic cables on Wikileaks)! They don't care that she recognized and supported illegal governments in Honduras and Afghanistan.
This is my conclusion. They seem to love her for being a popular socialite and public figure for a long time. They have an arrogant belief that she has a right to be the President of the United States simply because she's Hillary Clinton. They care about her celebrity, not about issues. They want to claim superiority to people who don't support her, claiming that only a sexist or an idiot couldn't want her to be all-powerful. Her following is a cult of personality. Talking to a cult of personality about politics is like talking to a religious cult about spirituality. There's no sense in doing it.
Let this be the end of it. I won't make unprovoked attacks on Mrs. Clinton's supporters or their character, to their faces, and neither should any of you. I'm only making the case right here that there's no use in talking to them. Please, let's forget about that. They'll only attack us.