A classic story involves blind men encountering an elephant. Each described what they perceived with their hands, and decided that they knew what an elephant was based on their perception. We laugh at the story because the blind men are all wrong, and we can easily know this because we can 'see' an elephant.
Blind men and an elephant - Wikipedia
Similarly, people with sight might see a martial art technique and decide that they know what it is, what it is for, and decided whether or not it is of value, without any true understanding of the true reasons behind the technique.
This gives rise to several errors. The first is obvious - there is a technique which will be rejected by some because they do not 'see' how it could possibly work. The second is more insidious - it involves those trained but apparently not to the extent that they grasp the concept either. These will also claim that a technique, or even a style of martial arts, is valueless because they either could not grasp it or it was not taught to them by a person who understood it.
I have heard this expressed in many contexts, usually over the traditional martial arts.
Kata is one. Individual techniques or training methods. Ways of standing and moving. Even basic concepts like respect shown on the training floor via traditions like bowing and terms of respect.
If you are a student being shown these things, I would urge you to show patience and trust your instructors. If it is not becoming clear to you, ask questions, seek clarification. A competent instructor should always be able and willing to demonstrate the 'why' of what you are training.
If you're an instructor, I hope that you understand these things and are passing them along as best you can.
And if you're just an observer, or a specialist in another style, who thinks they know what a kata or a technique or a practice is for, I would urge you to try to find out more before condemning it out of hand.
Otherwise, the elephant is just a snake because you touched its tail and think you understand it.