If my scumbag sibling killed someone and I didn't say they were a scumbag and distance myself from them and instead defended them and enabled them to continue being a scumbag I damn well deserve others' ire.

You immediately got it wrong. You didn't know they were scum. You maybe knew. You didn't really know though. For the same reason mass murderers can be saints to their communities. Lying to people is easy to them. And most people are believing.

Your sibling was completely normal. Maybe hot headed. It came out they killed someone. That's it. You're not going to toss them under the bus. In general you'll wait because that's your family unless someone knew better.

You are officially defending them at that point according to you. No matter if he legally or morally got off or was culpable.

It's dumb. The entire ACAB stance is dumb just on its premise. Y'all too fucking gullible to Russian and Chinese propaganda lol.