> Either we let the sidewalk become a free for all or we don’t

Why? You already demonstrated that we are able to acknowledge scooters and wheelchairs. That shows that exceptions can be made. They were made on some basis that is not all or nothing. Likewise we can review the basis here and decide that robots are not allowed or we can decide that robots are allowed.

It’s a collective space and how we collectively allocate it is useful to consider. I’d happily take wider sidewalks if it meant admitting robots for instance.

There’s no reason to believe this is a walk-or-nothing situation. In SF, for instance, children do not need the sidewalk to travel on their bikes but they are permitted to use it.

“generally”? I live in an area of the USA where AFAIK bicycles are officially dual-mode and allowed to be on both roads and sidewalks, and have been on both sides of pedestrian/bicycle encounters on sidewalks in the past, without any major issue.

From the article it sounds like the Pennsylvania legislature has already considered the case of delivery robots specifically and decided that they should go on the sidewalk, though to what degree that reflects the popular will is unknown to me.

> but we generally don’t accept someone on a bicycle or someone skating

I see people on rented scooters/bikes on the sidewalk all the time. Society at large seems to absolutely accept this. (note that I'm commenting on the current state of affairs, not what I think ought be the case)

> robots on wheels.

Robots owners got big bucks which means power. They need ROI, not sidewalks (also, guess do they use sidewalks or cars?).