For us, the answer is part habit, part convenience, part long times between trash loads leaving the house, and part power-tool joy.
Habit and convenience: it’s easier to just peel a carrot into the sink – those peels fly all over the place. Likewise, it’s easier to cut juicy stuff like tomatoes up with the cutting board jutting out over the sink, and when finished, to just tip the board in and rinse it off. If it’s not winter, we try to save stuff for compost; however, as we are lazy housekeepers, sometimes the in-kitchen compost container gets stinky and someone will dump & grind.
Trash latency: We don’t have garbage trucks in our town. We have to haul everything to the “transfer station” (dump and recycling collection) ourselves. We don’t generate much trash volume; it takes at least a month, sometimes two or three, to generate a mini-pickup-truck load. (Meanwhile bags of trash and recycling wait patiently in one of our three sheds.) So we try not to put anything stinky in the trash at all – we rinse out unrecyclable dairy containers, for instance. It helps that we rarely cook with meat.
Power-tool joy: like the Brit in the linked article, we find it really fun to run stuff through the disposal. GRGRGRGRGRGRGRGRGRGRGRG!
In some other places, in Seattle for instance, you’re admonished by the city not to put that stuff in your trash. Of course you’re *supposed *to put it in the yard waste & compost container for curbside pickup.