I think the point is here that most people would expect to see the parents make some cut backs first.
And if they aren't prepared to do that then why should we pay more?
A large portion of these families will have been on universal credit before covid and after so there is no real change for them, except they have had to do a bit more parenting, had more time to bond with their children while schools habd been closed.
Parents shouldn't have children on the assumption that they will be entirely paid for, fed, educated, clothed and brought up by the state, with no input from the parents.
Many people feel aggrieved that this is exactly what is happening and that irresponsible people are having children (or multiple) and literally handing off all responsibility to the state, and therefore us as tax payers while the parent simply benefits from free housing, free money, no other a life of luxury, but one of disregard for personal responsibility and sacrifice to make the family work.