I don't think human right activists and journalists are the most at risk here. They are more at risk than you and me but at least, they can keep a low profile.
CEOs and celebrities and politicians are not only at risk because of their influence and insider knowledge, but they also have a huge target painted on them at all times. They simply can't keep a low profile due to their occupation. They also have money, much more than journalists and activists, so they attract "regular" criminals too.
Human right activists and journalists probably won't be their main user base but it will be the most prominent for public relations reasons, because who doesn't like human right and investigative journalism? VIPs are less marketable and let's not talk about criminals. To keep things clear, I think it is a good feature, even if it can help criminals. After all, human right activists are often technically criminals where they act.
Many journalists whole job is to not keep a low profile and pull attention from the public. I'm not sure politicians get killed that much more in comparison [0]. Money is usually enough to solve political problems.
I have yet to hear about NSO tools being used to target celebrities who are not activists. Activists are targeted all the time. For example, Mexico used its NSO install to target a person that was working to get a tax on sugar sweetened beverages passed. And their children!
Getting world leaders, celebrities and CEOs to use their devices might make this part of their marketing budget.