The main thing to look for with motherboards (other than CPU compatibility) is the ports it has. Number/type of usb ports, ethernet speed etc. that's most likely to be the thing that annoys you if you buy the wrong one.
(PCIE expansion cards can fix most problems there though if needed)
It's probably a single dev that made the decision, then moves onto something else. They (probably?) don't have the ability to just raise a recurring PO etc to easily pay you and don't care enough to worth through the paperwork.
If you had a paid licencing model they may have done it, or just found another lib/ wrote their own.