Its a terrible idea but the subject is huge and would really require covering a lot of historical data, communism, solidarity, supporting Ukraine and Polish families already getting cash benefit 800zl for the children.
The draft aims to provide significant tax relief to families who have two or more children and the income threshold is fairly high even for Poland as its 140k zloty per parent ( 280k for both) so a really good salary in Poland. People on that salary definitely don't need tax break, and in fact that sort of tax break should be provided for parents who need it the most- those with disabled children.
Because it is a tax relief rather than a universal benefit, families with very low taxable income (or not working) may benefit less (or not at all) compared to middle-income working families. Some observers note it may favour those already doing reasonably well.
Eliminating PIT for a large group reduces tax revenue. The draft will have fiscal implications (for the state budget, social funds, maybe local governments). Now anyone living in Poland who is retired or sick will tell you of the cuts that were made in order to give to those with children. We know plenty of sick people who were told they were healthy enough to work and dont deserve health benefit ( disability pension). Dad's friend post severe cancer - healthy to work. Another one lost arm in work accident - healthy to work. My mum wasnt granted the benefit despite not being able to move due to her back and no feeling in one arm. They are all retired now but their retirement funds got cut down too because there just isnt enough in the pot. Pension rules are different in Poland so they worked and paid lots through workplace pension ( private pension wasnt much of a thing and still isn't) and fully deserve that money after 35 years.
Then you have the Ukraine drama. They were welcomed. Lots abused the system. Got everything for free. The demand of going into shops / hairdressers / doctors/ pharmacies not only demanding priority but also getting it all for free is something the news didnt show over here. I have witnessed some seriously bonkers things.
So in a short to give those benefits out to people, you've gotta cut it from somewhere else and its going to take away from people who aren't capable to work or already worked for the money they wont be getting now.