Yeah Heinlein was kind of a dick. Asimov, who was a good friend of his, said something after his death like he hoped Heinlein's personal journals wouldn't be published so he could be remembered only as a brilliant author.
> "Several years ago, when I was ill, Heinlein offered his help, anything he could do, and we had never met; he would phone me to cheer me up and see how I was doing. He wanted to buy me an electric typewriter, God bless him—one of the few true gentlemen in this world. I don't agree with any ideas he puts forth in his writing, but that is neither here nor there. One time when I owed the IRS a lot of money and couldn't raise it, Heinlein loaned the money to me. I think a great deal of him and his wife; I dedicated a book to them in appreciation. Robert Heinlein is a fine-looking man, very impressive and very military in stance; you can tell he has a military background, even to the haircut. He knows I'm a flipped-out freak and still he helped me and my wife when we were in trouble. That is the best in humanity, there; that is who and what I love."
There are multiple ways to be an asshole, and so maybe we should say Heinlein sounds like an asshole, but by many accounts was kind to those who knew him well.
“An armed society is a polite society” is one that's floated often today among those pro-gun.
“A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.”
I've encountered people that take these as him being a fascist, asshole or prick. Personally, I agree with him on both counts, and consider most people to be lack contributions to the human race for their lack of desire to learn and become competent, or for their inability to learn. If that makes someone an asshole, so be it.