The question is if in this case the action can be considered as deliberate. The "software" did it, is it deliberate? Is it considered as a failure of the car like the breaking of mechanical part?

This is new and the justice will have to figure it out and I am very happy not to have to figure it out.

I'd say there is only one car which did a clearly illegal action (sudden lane change followed by brake checking), so the guilt is 100% on them.

It's also true that the car behind probably could've been more assertive in braking harder to avoid reaching the Tesla (I wish there was a dashcam to see it from a better angle). But they didn't do anything illegal per se.

Also, that second car driver might've been worried of braking too hard to avoid getting themselves rear ended, which is a legitimate concern when having to break hard in traffic. Of course in the end they got rear ended anyway, but couldn't have known that prior to it happening.