There is NO excuse to kill someone just because you wanted to turn left and these punishments aren’t nearly enough.

That's not what was happening here, or at least there's nothing to suggest that's what was happening here.

This happened at 06:00. Sunrise in Tucson yesterday was approximately 06:15, so it was dark. Westbound traffic has a traffic light and is allowed to turn left. What ostensibly happened is that this driver had a green light (but not a green arrow), didn't see anybody coming, and turned into a bicyclist, killing them. A driver is being held to task for failing to properly operate a multi-ton vehicle – they're being held to task for their portion of the fault.

We can do both.

You can do both, but you have to do both proportionally instead of throwing up your hands and saying "well they both suck". Clearly, the bulk of the blame rests with the city, because a) cars and bicycles should not have to share this space, and b) any reasonable planner would foresee this kind of problem. This is horribly designed in a way that charging anything more than a misdemeanor would be unjust and a ridiculous stretch of consequentialism.