Who’s arguing for peaceful protest here?

Apparently no one here, though I think (possibly incorrectly) that the protestors in the article were intending to be peaceful.

And why is the binary of “peaceful/not peaceful” important to you?

I would ask why it seems to be so important to everyone else, given that there was so much resistance to the idea that blowing up buildings is not "peaceful".

Are you trying to make the point that protests aren’t valid or effective unless they’re “peaceful?”

It depends on what the goal of a given protest is.

For example, this protest had the goal of interfering with a developer conference in order to disrupt the recruitment of new talent, and it would seem that they were very effective in this because there was evidence that the event was shut down. However, in the long run I am not sure how much this will help because I suspect that the event will just be rescheduled, and I suspect that the people attending the event probably felt intimidated as a result of all the people banging on the windows rather than guilty for attending the event. (Just to be clear, I am not saying that therefore this was wasted time on their part; I am just saying that celebrating might be premature.)

Regardless, if nothing else, the protest succeeded very well in being very visible and unignorable, and I think that there is a lot of value in that. Certainly I would rather that they do this kind of thing than that they be casually blowing up buildings as many here would prefer.