It’s just something I hear a lot.
While I’m here, let me leave another Inika-related headcanon. I think we can accept it as necessarily true that if Matoran transform into their ideal of a Toa when transforming, then it must be the case that the “default” body plan of a Toa evolves over time. Taking this, it must be true that the way that the Toa Metru look, for example, is not necessarily the way the first Toa would have looked. It is also true that when the Toa Inika transformed, they did not transform according to their ideal as Toa, but were transformed according to what was essentially the will of the red star.
My headcanon, then, is that the Toa Inika were transformed according to a more “basal” (to use an evolutionary biology term) blueprint of a Toa. The red star’s Toa creation failsafe would have been programmed directly by the Great Beings (the Kestora could not have programmed it), so it likely would have been designed to create Toa as they were designed by the Great Beings, rather than a more “derived” Toa form. We also know that the original Toa were based on Glatorian, so it makes sense that Inika-style Toa would have the similar long-armed proportions of the Glatorian species. One more piece of evidence comes in the form of Lesovikk - he is a very old Toa whose body is an Inika build. The Toa Mata and Toa Helryx do not have Inika builds because they were essentially prototype Toa. Lesovikk is among the oldest known Toa to have a physical appearance, and would have had a more “standard” creation than Helryx or the Mata. All of that taken together, then, mostly serves to justify the weird long-armed proportions of the Inika build.