Why is the default, go-to protest chant always "Hey hey! Ho ho! {person} has got to go!" ?

The point of a protest is not to rationally convince the rulers to change. By the time a protest occurs, the "rational" and "legitimate" options have been exhausted. Protests are a show of power by subjects to their rulers, and a threat that more serious consequences will follow if nothing changes. The fact that a mass of people have assembled and are taking action at all is sufficient for a protest to be effective IMO.

So I don't think "basic" slogans make protests less effective so long as they don't oversimplify the demands of the protesters. Similarly, creative slogans can definitely help protests be more effective if they sharpen the message they intend to deliver.

consistancy is more the drive. the signs already tend to be very individualistic but you don't want everyone shouting different things so you want to keep it simple.

Because people already know the chant and it’s dead easy to follow along and learn.

It’s not the words themselves that are effective. It’s the number of people saying them together. Chanting and singing in unison has a very powerful effect on human psychology for both the chanters and people hearing it.

Walk into almost a church to witness this effect, watch soldiers doing drills, listen to cheers at a sporting event. People are stronger together, we feel that at a fundamental level. Hearing people making the same sounds communicates unanimous intent. That can be inspiring or intimidating, it doesn’t matter much what words they say.

I’ve been to a protest where the organizers announced what the chants were going to be. The alternatives were…terrible.

Because the only defense against it is having an awkwardly long name.

Sounds like a avril lavigne song

I mean, just because people know the pattern, I'm sure. Most of the seasonal music, in American culture at least, sucks, but people know it and so it lives forever.

I've never heard that before, but I do know that protestors aren't very creative, which might be why they fail as much as they do.