It definitely seems they could and need to do more to tighten up the accountability on the platform. No doubt about that.
I don't know that it's accurate to say the contractor doesn't care. If they were a psychopath I could agree with that, but most people have had the experience of having either a pet, friend or relative die and know how deeply it affects people emotionally and to know you were responsible for that would likely generate a strong, negative visceral reaction.
Edit: Platforms don't kill dogs; people do. Stop trusting people.
Actually this is the part that fascinates me. On some level people expect things to never go wrong. Yet things going "wrong" is kind of the default. It's extremely hard to engineer a situation in which no one ever experiences a negative outcome. To the extent that you can attribute a cause to an outcome, you do.
Infact, it's not at all clear whether the frequency of dogs dying while being sat by pet sitters is higher on platforms or higher when not through platforms. You'd actually have to do quite a lengthy, expensive analysis to compute the truth value of that.
What can likely agree on is that we want the most safe and convenient system. I'm fascinated by thinking about the various trade-offs made when organizing a system one way vs. another. Are we trading more convenience for less safety? Or are we actually getting both more convenience AND more safety, but also increased observability is skewing our perception of the risk such that we think we have got a less safe system when in fact the opposite might be true?
I don't have the answers. But damnit it's important to attempt to look at things the right way in an attempt to compute that actual reality.