Fact: Hamas commits and have committed acts of terrorism and therefore Hamas is a terrorist organisation.
It doesn't matter what other countries have committed terrorist acts now or 100 years ago.
There is no connection or dependencies.
Hamas is a terrorist organisation because of them committing acts of terrorism.
End of story.
When BBC is asked to call Belgium a terrorist start you're free to discuss that there. In that thread I will happily claim that Hamas is innocent to whatever Leo did in Africa.