This topic is not about child benefit. Like you I have reservations about the payment of children's allowances to EU citizens in Ireland whose children are (perhaps!) in their country of origin.
What the Polish government is trying to do is to encourage mothers to stay at home to rear their children. When mothers (or indeed fathers) leave the workforce to rear children they lose out on the Polish equivalent of PRSI and do not qualify for an old age pension in their own right which could be a factor in their deciding to do paid work or not. So in effect the Polish government is giving the mothers of larger families credited PRSI contributions which mean she qualifies for a pension in her own right. To some extent this happens in Ireland. If you are rearing a child under 12 here you can apply for PRSI credits for a certain period.
Hopefully all the polish will return home to their own welfare state.
I criticised a conspicuous act of vote buying by the Polish government, so therefore I'm in favour of the mass importation of Somalis and Bangladehsis?better to bring in Somalis and Bangladeshis.