So there's a few things here.
> Only there is no 'oppressive system'.
I think this is open to debate, and it's not fair to simply state it as fact given the evidence.
> ... but an individual officer responding to 911 call and standing against an agitated individual with a weapon and who's about to attack.
Indeed, but that's also overly simplistic. A violent response is justified but isn't necessarily preferred, and degree matters. Proper training in de-escalation, hand-to-hand combat, safety equipment, non-lethal, less-lethal and eventually if necessary lethal weapons are all available to officers.
How you pick is a systemic question. How much training and what kind is a systemic question. And the results are measurable. Indeed Canada's per capita police shooting rate is 1/10th that of the US -- and Canada's pretty high as far as rich countries go! New Zealand police killed 2 or 3 people since 2015.
It's overwhelmingly not a kill-or-be-killed situation, and further, the job of an officer is not to eliminate 100% of harm potential for themselves at all costs -- but instead to resolve the situation with the optimal outcome for all involved. The job is in fact risky, which is why the profession is so highly regarded.
I maintain the issue is one of accountability, between police not being held accountable for gross negligence, the unequivocal support from the police unions and of course, qualified immunity. I suspect people just want to feel like they're being treated fairly. If you don't hold anyone accountable it creates a negative feedback loop breaking trust and making the job more dangerous for everyone.