At least in the case of the heart, there’s the beginnings of evidence that is suggestive of the fact that the damage is not simply incidental to systemic inflammation. https://medicine.wustl.edu/news/covid-19-can-kill-heart-musc...
One thing missing, for example, is why this doesn't appear to happen frequently. Most of the highly touted claims of cardiac involvement from summer 2020 have been debunked (e.g. in athletes).