The point is not to get people out of being single.There are already way more then that single and not wanting to be in a relationshop so I doubt it would have a big effect. if anything it will get more people out of single relationships.
I'm just not sure how they would work out tax deductions.
The point is to give those without mates, a chance to have one.
Go read some economics books. The whole point is that by giving people something to do, i.e. a job, you give them dignity, identity, status, and stability.
When you take away the ability for someone to get a mate that they'd be suited for realistically, and give it to someone who can provide for many other mates, you take away the opportunity for segments of the population to engage in the existential process of obtaining stability.
Societies can't function if there are expanding segments that can't even fulfill core aspects of their identity, by seeking mates.