I assume you’re asking as someone from outside of Australia?

Anyway, answering only from personal / anecdotal experience:

Are people openly talking about the genocide in Gaza or is it considered some taboo topic?

Seems fine among the politics-is-okay crowd. Not sure about the don’t-care-about-politics crowd, but it makes national news often enough that I doubt it’s unusually “taboo” compared to other subjects that tend to be politically or emotionally charged.

Do people get fired for saying genocide is wrong or the the people in Gaza have a right to live?

Are people getting dissapeared for expressing solidarity with Palestinians like they are in the USA?

Not that I’m aware of, in general. I know some student protests were cracked down on earlier this year but we weren’t deploying snipers on campuses at least.