The same reason millions of Americans voted for "trickle down" and other irrational economic decisions. They're overly manipulated by propaganda.
I guess a similar lie for repairing products would have to be something like - the possibilities of modern manufacturing have progressed to such a point that it is simpler, cheaper, and easier to make longer lasting products that do not need to be repaired if they, paradoxically, are made in a way that makes it impossible to repair them.
I actually do not know enough about modern manufacturing to know if the above is false but I assume it must be as I have not heard the argument, and I just made it up now, it seems unlikely I would make up an argument that was also true. I would also of course be unlikely to believe the argument given that I would see how it was made to the benefit of the people who would profit from its truth, and at any rate it would make it easier to make built in obsolescence a part of the manufacturing process.
But anyway that would be my example of a similar argument to trickle down in the context of right to repair.
Like with most of the half-truths you find on the internet, it seems plausible but without evidence such as how often Apple were reseating RAM in laptops we have no way of really knowing how accurate it is.