Why is 'all lives matter' rude?
It's NOT! It's just that everyone knows that .... but if it's a black life ... wtf? At least that's the attitude of many conservatives and racist cops! The GOOD cops know better, but the cop unions have a job to do and they, dutily, protect their own, so, black lives seem to matter less than white ones. Simple. You'd think simple minds would comprehend, but, they don't. And therein lies the problem.
The majority of Americans realize that "black lives matter" is just pointing out that some people don't seem to realize black lives matter TOO. But, I digress............. :-)
A couple few illustrative examples:
If your wife asks "Do you love me?" and you answer "I love everyone"
If a friend says to you "My father just died" and you reply "Lots of people die"
If your house is on fire and you call 911, and they say "All houses matter"
And if you are aware that the founders of the movement are Marxists using the term as a shield to propel their tyrannical ideology, you say "all lives matter" because they do, and you are daring the movement to admit otherwise.
Secondly, if cops shoot more of another demographic, you are pointing to the hilarity of a demographic that's shot less being the only one applied a fake, Marxist victimhood status and daring them to give you the opportunity to paste them with actual facts, data and statistics.
The ad hominem labels may persuade some people, but I (and you should) know better.
"daring the movement to admit otherwise"
They readily do.
"cops shoot more of another demographic"
Blacks are shot more than whites per-capita, and while that stat can be interpreted multiple ways, being shot by cops is not the only evidence of extant racism.
Why is there backlash to something so seemingly innocuous?
Why don't you sit down and strain yourself. See if you can work it out. Here, I'll give you an example.
Hitler gasses a bunch of Jews. Some Germans protest that Jewish lives matter. Hitler lectures them about how all lives matter and gasses them for being racist.
The title of what is in effect a political statement is one word shy, namely, Only.
The full logo should read Only Black Lives Matter.
In time, probably a short time, the term will be expanded to;- Only Black Lives Matter you white bastards.
If The Bongo really believe their pitiful slogan then why don't they stop killing each other on an industrial scale.
Maybe cops do kill more blacks proportionately than whites but that is due to the Bongo's significantly higher level of violent crime and them savagely resisting arrest.