John Brown was a based terrorist. The British Suffragette movement had a bunch of based terrorists. Mother Jones was based, and as much of a terrorist as most of Al Qaeda (i.e. not personally involved in terrorist attacks, but supporting movements that did engage in terrorism).

All you need is a sufficiently abhorrent status quo and terrorists who are otherwise decent human beings.

Violence: behavior involving physical force intended to hurt, damage, or kill someone or something.

Specific to Australia, terrorism: Terrorism is defined as "an action or threat of action where the action causes certain defined forms of harm or interference and the action is done or the threat is made with the intention of advancing a political, religious and ideological or group cause".

These climate protesters in the US were convicted of terrorism.

How much do you want to bet this, or actions like this get called terrorism? It fits the definition if you want it to, which is all that matters. Yes, it's bullshit if they call it terrorism, which is why the word needs to have its negative connotation stripped. There have been good terrorists in the past and there will be in the future. The word has no mention of it being done for evil purposes.