Flamestrike
Legend
No, you're parsing the text wrong:No, not in my copy of the DMG, which is from FG, and therefore is supposed to be updated will all erratta.
Here's the full quote;
Normally, creatures in the Border Ethereal can't attack creatures on the overlapping plane, and vice versa. A traveler on the Ethereal Plane is invisible and utterly silent to someone on the overlapping plane, and solid objects on the overlapping plane don't hamper the movement of a creature in the Border Ethereal.
The exceptions are certain magical effects (including anything made of magical force) and living beings. This makes the Ethereal Plane ideal for reconnaissance, spying on opponents, and moving around without being detected. The Ethereal Plane also disobeys the laws of gravity; a creature there can move up and down as easily as walking.
If I parsed the text the way you are parsing the texts (read those two bolded lines in isolation), then two exceptions can 'attack' things in the Ethereal plane:
1) Magical force effects, and
2) Living beings (non undead or constructs)
In other words, your parsing leads to a situation where one doesn't even need a magical force effect to attack someone in the Ethereal plane, if one is a 'living being'. Harry the living human Monk can punch an Ethereal creature in the face from the Material plane for example, if I used your parsing of that text.
The exceptions in the text above, refer to living creatures and magical force effects blocking movement on the Border ethereal (the exceptions in the first line of the second paragraph refer to the second part of the first paragraph only) as reflected elsewhere in the wall of force, forcecage and similar spells.
The exceptions (in the first sentence of the second paragraph re living creatures and magical force effects) do not apply to the first sentence of the first paragraph, which prohibits attacks being made from the material to the ethereal (full stop).