This explains it, top to bottom:

“This isn’t about mutual tolerance because there’s nothing mutual about it. If we agree to disagree on this issue, you walk away a full member of this society and I don’t. There is no “live and let live” on this issue because Dan Cathy is spending millions to very specifically NOT let me live. I’m not trying to do that to him.”

And really, it’s helpful to see what kind of people will go out of their way to support bigotry.  It’s more than one might guess, nevermind might hope.