Because, if you enabled it on the port, it wouldn't be enabled on wireless (VLAN bridge). And to be clear, some devices allow you to set this on the switch.
Since you have the same behavior in both instances, it should be OK.
Correct, most devices looking for multicast packets, expect them to be UDP. There's a thread on this forum where posters had the same issues converting to unicast...I think this thread, beginning around post #53 may be helpful: