Anthropic's guide for job applicants on how you should use Claude when applying for a job there is relevant here: https://www.anthropic.com/candidate-ai-guidance
Anthropic certainly isn't planning to take responsibility for Claude's mistakes - that's the user's responsibility. Describing everything as 'collaborating' is I think part of their efforts to emphasise the user's role in the process.
I trust the output of colleagues I am collaborating with and have an assumption of some shared responsibility. But if I use a tool like numpy/matplotlib then I am accountable for the conclusions I come up with. I can't make an excuse that "matplotlib" created a plot so my decisions were incorrect and not due to my own negligence.