Even if you're selfish, free healthcare for all makes sense. A 28-year-old who doesn't work can still be a disease vector, and if they don't stay healthy now they will be an even bigger health burden later in life.

I think it's less selfishness than a morality derived from:

• slave-owners, who had to force enslaved people to work
• puritanical christians who assumed human nature was naturally lazy and immoral
• zero-sum business owners who don't want to see others "get ahead" in ways they hadn't
• people who believe raising a family isn't "real work", just something you should do between jobs