Interrupting a speech? Yes. It demonstrates a lack of maturity, decorum, and is completely unprofessional. Someone who pulls these shenanigans is unworthy of the role they were hired for. This isn't high school anymore. They were hired to perform productive work not be disruptive and play pretend activist.

You lost me at "pretend activist". This person put their job on the line for what they believe in, and in a public enough way that complete strangers are discussing it on the internet. That's real activism.

If they don't like it, they don't have to work there.

All these people hate on their employer and customers whilst simultaneously drawing a salary.

If they put their money where their mouth is, they can all quit en masse and let the company deal with customers without employees to support.

In general, continuing to get paid while being disruptive and forcing them to fire you is more activist than quitting.

If they don't like it, they can voice what they don't like. And that is what happened here.

When doing a presentation at a big conference, yes.

If it was an open discussion in a meeting with 5 people, no.

You are trivializing what they did. This is not that they were in a meeting with the CEO and accidentally spoke interrupting him. They started yelling disrupting the CEOs speech at a large event. Name a single company that wouldn't fire someone for that.