I think that a part of the requirement to be a great writer is that you have to be an asshole, with Harlan Ellison the ur example. Never meet your heroes, death of the author etc.
Larry Niven is weird, but he's not an asshole. Greg Bear is a warm and welcoming gentleman. Geoffrey Landis is awesome. Douglas Preston is a great dude. I never met Octavia Butler, but everyone at her funeral had nothing but good stuff to say (except Harlan Ellison, who made it all about Harlan Ellison). My interactions with Tony Hillerman were great. Jerry Pournelle and Harlan Ellison are outliers, not the norm.
Please. No. Don't let this be true. Stan Sakai seems so nice! I'm sure he is in real life. There's gotta be a few outliers. I took a few creative writing classes in college to help fluff up my grade average (if you showed up to every class, put in effort, and tried to understand the material, you'd get a good grade) and there was this student in one of my classes that was super talented. Literally everything they turned in for group critique couldn't be critiqued because we all liked it so much. They were the nicest, quietest, most modest person I've ever met. I haven't thought about them in years. If I had their number, I'd call them up right now to say "howdy" and just to see what they're up to.I think that a part of the requirement to be a great writer is that you have to be an asshole