Dumbbells and barbells, with lighter weight of course.

That is frankly dumb reasoning. You can still injure yourself doing bodyweight exercises, especially if you're not strong enough to handle your own bodyweight.

In fact, some exercises like chinups and pullups require you to train on machines to increase your arm and back strength before you even try doing full unassisted pullups/chinups.

Machines are good for beginners since they limit the margin for error and don't put as much strain on your stabiliser muscles.