Subsidizing private education?

Hrmh... I am listening to a local news radio station. Of course, what I am about to write lacks information and insight — but it follows a conversation I have had with several groups of friends.

Our de-facto president has decreed that the tuition for private schools will be deducted from the Impuesto sobre la renta (revenue/profit tax) up to a given tuition level (IIRC up to MX$2000 a month per child per school). The interviewed subsecretary said they expect this deduction will reach MX$13,000 million, around US$1,000 million. This is, about a third of what is assigned to the National University (UNAM).

At a first sight, this sounds good. However, I just thought about a discussion I have had with many friends. This money the government will hand back to the taxpayers has to be cut from somewhere (after all, we are not in a country with huge superavit or anything like that).

Why does this sound unfair ot me? Because it benefits the few in perjudice of the many. I did a quick search, and found this work based on numbers published by INEGI ten years ago: According to the last table, the money spent on private education was between 5% and 10% of that spent on public education — Of course, it is almost impossible to infer the number of students from this alone. I know I could find authoritative data on this regard by searching a bit more, but after all I don't want to spend all (work!) evening on a blog post unless it creates some discussion. Lets say, just for the sake of the exercise, that this means that ~3% of the country's students learn in a private school.

In Mexico, the quality of the basic public education (primary/secondary, ages 6 to 18) has fallen hugely in the last decades. Even when I was to school (but not when my parents), the first subjective sign that a family had broken the low-income barrier is that they were finally able to send their children to private schools. Because, no matter how bad they are, public schools are perceived to be worse. Of course, I was among the "lucky" ones to be in a private school. Higher education (universitary level) is still way better ranged.

Anyway... I want to get this post over with. Why do I oppose this subsidies/tax devolution? Because it will lead to widen the difference between private and public education. And because it will be benefical only for medium-high and high classes — People who are formaly employed (as I am) do not present a tax declaration, so we won't get any deductions. Between ⅓ and ½ of the country's economically active population work informally (from selling in the street to covering up huge transactions in large locals). Most of the population don't (directly) pay "impuesto sobre la renta", and will not get the benefit of this subsidy.

This money has to be taken from other sources in order to be given to private education. If the government wants to improve the education for everybody, why not assign it to the public sector? To specific areas in the public sector, if they don't want to hand it over to the (yes, very, incredibly) corrupt SNTE (National Union of Education Workers)?