My wife is a stay-at-home mom. We are lucky that we can afford to do this. Most of our kid's friends have both parents working and they pay for child care. If suddenly they were able to have that childcare paid for, that would be wonderful! It doesn't affect our situation at all. Why would we oppose it? I don't need to have my own "waiver" payment in order for me to be in favor of my neighbor's burden being lifted.
It's like free school lunch. We pack our kid a lunch every day, but some families rely on the school-provided free lunch. It's never even occurred to me that we should get a $3/day payment because we don't take advantage of free lunch. Having free lunch available is unequivocally a good thing, regardless of whether we personally partake.
> It doesn't affect our situation at all. Why would we oppose it?
This is rather noble of you, but the reason is obvious. If the playing field were "levelled" then you wouldn't have to be lucky. It is all well and good that you are lucky, but there is a certain population who want to emulate your choice but are unable to, because they are missing precisely the marginal amount that the childcare provision costs. It is a political choice to say that those people should not be able to pursue home-care of the children in order that we can avoid giving out a rebate.
But the lack of that subsidy should not cause someone to oppose a paid-childcare subsidy.