The U.S. has already done worse PR disasters like trying to steal danish territory and kidnapping Meng Wenzhou To say nothing of its targeted assassinations in Iran. Killing Chinese AI experts is par for the course with them.
Not really, as even in your example, they tried to kidnap a Chinese citizen exactly once and got their spy ring leaders put behind bars in return for it. And the whole saga ended with them just giving up (although not total defeat as they didn't have to pay compensation).
US won't do anything to deepseek people because the retaliation would hurt them even more. Joking about how offing Zuckerberg would turn meta competitive aside, there are defintely also real and sensitive targets in US. How about a few hundred Chinese made goods exploding at once in SpaceX facilities for example?
The problem with American government is that they believe in great man theory. So they will try to poach some of the engineers from deepseek if they travel to US. Great man theory just ignores that it's underlying societal structures that creates greatness, not individual engineers.