Learning objectives help teachers plan. They do not help students learn.
Some time ago, I wrote about the problems with Discovery Learning Experiments. On closer inspection, I now see that the problem I was describing was really with one of the most celebrated aspects of "evidence-based" education: learning objectives (also called "learning intentions").
The airport analogy shows how it is easy for students to learn many other things than what were intended. Free exploration can lead to a ton of learning, but when simple learning objectives and success criteria are used to evaluate the results, only the learning that falls into the desired boxes is rewarded. The harder teachers work to reward the learning intentions, the more they communicate the idea that nothing else matters.
While in the early stages this can come down to a simple self-induced blindness on the teacher's perspective to notice any learning other than what they intended, in the long term it also discourages independence on behalf of the student.
When learning is only valid based on ticking predefined boxes, the learner begins to shy away from true creative and independent thought. They complain when the maths teacher asks them to correct their spelling, saying "This isn't English class!". If it's "not on the test", then attention drops by 95%.
There is nothing wrong with students. They are behaving totally rationally given the constraints imposed on them. This is the catastrophic long term harm caused by the attempt to micromanage the learning process from the outside. Either the student eventually submits and, like a broken-in horse, does only what they're told, or they become a rebel.
If it's so bad, why do they do it?
The idea is simple: to teach someone something, you must have a clear idea of what you're trying to teach them, and everything should be focused towards that goal. This makes perfect sense as a communication strategy. If you're making a video, or a lecture, or some other educational resource, there should be a clear point to it. The problem arises when that thinking pours over into the learning process itself.
Metaphorically speaking, a chef needs to have a clear idea of the menu they want to cook, but a guest should have the option of choosing whether or not to eat it. If they order a dish, they should still be able to push it away, uneaten, if it's not what they thought they were getting.
Rather than simply helping teachers structure their communication more clearly, learning intentions have grown to take over the lives of every student on the planet. They all get set menus, without being allowed to let their mental taste buds decide what is actually working for them.
Recently, education systems have pushed teachers towards "evidence", and away from thinking for yourself. We are provided with HITS lists of "proven" strategies (you'll notice the first is "setting goals").
Scale of the problem
Teachers have learning objectives in each lesson, textbooks have learning intentions for each chapter and school systems have learning objectives for every student of every level. This is considered best practice.
For the sake of consistency, choice is removed from teachers and students and replaced with the same set menu for everyone. This creates a McDonald's of education where it is easy to deliver the same thing every time, but all creativity and initiative is removed, thus putting a ceiling on quality.
Of course every educational institution should be able to decide what they want to offer, and teachers should be clear about what they want to communicate. But on the other side of the table, students must be able to choose what they want to order from the menu, or if they want to order from that institution at all. After all the internet now provides an unofficial menu that ranges further in every direction than the official, state-prescribed curricula.
As of 2020, just about every aspect of education, from preschool to university, is defined in terms of learning objectives. It is time to start using learning objectives only for designing content and resources, and let students choose what to learn based on what integrates best with their existing knowledge.