Institutions do not magically get absolved of their sins just because time has passed
Furthermore, hold responsible in this context means basically to acknowledge that the past actions were wrong, which is a pretty low bar as far as responsibility goes.
At some point all of the criminals who did the thing in the past are dead.
Institutions can't act, because they have no brains or hands: only human beings can. You can't convict an institution of a crime, nor put it in prison.
Besides, we're talking moral responsibility not legal.
The only entities that can take actions of any kind are human beings.