This whole narrative being endlessly promoted of "all cops bad, all blacks good" is ridiculous.
That's a large bit of hyperbole. The original narrative is specifically a dual one; that there is an institutional problem with how police treat minorities as compared to others in the U.S., and has been for over a century, and, also how police treat citizens in general.
Certain extreme right personalities know this narrative is one that is relatively easy for ANYONE to support (except for the people who worship authority, no matter what), so they re-spin it to create a strawman to shift the argument to a strict "us vs. them" thing that is easier to use to polarize their followers. They shift things like "black lives matter," which is a statement that black lives are not less valuable than others people, into a statement that ONLY black lives matter, and then report it as such to provide an easy strawman argument to argue against. Biased listeners don't even recognize those tpes of strawmen and argumentative tactics, and they repeat the filtered argument as the ACTUAL argument, and bam, the narrative shifts more towards what you are intending.
This is probably less evident for people that don't live in the U.S., as they are typically getting the post-filtered reports as opposed to the original 24-hour news cycled reports blasted in their face constantly BEFORE the personalities get a hold on them and put even more of a spin on them; which would probably explain why people keep getting confused as to your opinions on what's happening here as opposed to the reality of what is happening.
Even in this thread (not to mention the other, related ones), we have people speaking of things filtered through the most extreme right wing personalities, who raise things to a level of fearmongering. To realize how ridiculous some of them are, the LEFT in America would be far, far right in most of Europe.
That's also why the "the truth is in the middle" stance is not really a default when it comes to these cases, no matter how reasonable a stance that can be at other times - normally, the point being argued has already been taken AWAY from the "middle" because it has been filtered through one or the other partisan sides to an extreme that only has a yes or no answer to it.