Why does it bother you? Part of the appeal of the streaming services is the long tail. That shows produced / funded by the service will remain indefinitely. That's become one of the expectations. When expectations are broken, people become unhappy.

In the case of Sesame Street, at least the missing episodes are available on Youtube. That mitigates things somewhat. But it's a shame the other shows were removed completely with no legal way to find them. I hope the resulting blowback is enough to keep streaming services from doing this again.