There can be very legitimate, child-focused, reasons why 50:50 shared time may not be appropriate. It’s not always a case of withholding or anything nefarious or sinister.
Generally speaking, a very young child, pre “school age”, has a strong attachment to one parent. In those cases, the general thinking is that to ensure their secure attachment is unaffected, they live with one parent and spend meaningful time with the other parent. It’s obviously a tricky and delicate time for the other parent as they are keen to build and maintain a solid bond and attachment too.
Once children reach primary school the general thinking is that the idea of 50:50 shared care can start to be put on the table. But it’s never a presumption. Always depends on individual circumstances and the needs of the child.
I have no interest in defending Moaning, but on this topic I don’t have concerns.