It is not unusual for any speaker with a vibration-dampening silicone base to leave mild marks when placed on some wooden surfaces.
But they just don't give a shit; They sell it, you either buy it or you don't. Just like when they slowed down the phones and every other fault, they really don't care how it affects you, just whatever it takes to get you to buy it.
I especially don't care. I know a thing or two about lithium batteries- so unlike every other angry moron on the internet who doesn't, I actually don't care one bit that apple is slowing down my phone for a totally justifiable reason.