Is not contradictory actually, what it says is that you could use the hole disk without any partition table (requirement) or if you already have DOS partitions created, then you should use fdisk or cfdisk to change the partition type to 0x8e (LVM).
IMHO, I would rather use fdisk, cfdisk or whatever to create partitions and then arrange the LVM structure from there since (to me) I will have more control over the partitions from the beginning. This would be good if I need for instance a /boot partition which can't be in the LVM scheme.
LVM has a very specific use in a system, however, maybe not every partition or disk needs that specific use, what doesn't need to be on the LVM (becuase you won't gain anything with it) doesn't have to be part of it, so it will be better to set through fdisk or the like a basic disk structure and from there create the LVM with the disk space that need to be part of it. That's what I mean with control.
But of course, that's just my opinion, others could think different