For the amount of synthetics in the area...well the whole "race" isn't even that old. This isn't a social movement that's had time to stabilize - and for spawning a whole new life-form, that could take hundreds of years.
When this comic started there was only Pintsize, who was eventually joined by similarly-configured AI's, and perhaps a few specialized ones such as that Vespa. While others, including humanoid AI's, existed in background canon (we now know), they were not present on-scene.
It looks to me like Young Jeph intended Pintisize et al to be "joke characters" but as the comic grew more socially-conscious, more diverse, and leaned toward justice, the AI's grew from a joke to a serious subject (which I'm fascinated by, in fact; I love how he's been handling this). In-canon, I can easily view this change as part of the social movement happening in the background, as robots find their place from being novelties and "companions" to fully autonomous members of society.
Also the return of Brun at last! Bruuuun! <3 (She's become my favorite character).