> It means those who cannot find partners to make families are further punished, making their chances to create families even lower.
Incentivization of family formation would push people to get married, it would not make family formation less likely. The entire point of incentivizing a behavior through providing benefits is to make it easier for people who partake in that behavior, therefore drawing people to it.
> They're turned to a literal slave caste to provide for other people's families.
I'm single, and due to various factors it's unlikely I'll be getting married in the immediate future. I'm one of the people who would be "punished" by my "down-right evil idea" but I still think it's good. Economic pressure would definitely make me more invested, not less, in getting married sooner. Calling this a creation of a "literal slave caste" is an extreme emotional exaggeration since I'm definitely not calling for myself to be enslaved by any meaningful usage of the term.