Despite what the Declaration of Independence says, all men may be created equal, but once you come into the world, no men remain equal. Long ago we were dominated by those who had physical strength, or could throw rocks and sharp sticks the farthest. Later, if you were born into royalty, you automatically became the king, no matter how inbred or unfit to rule you were.

Now, money is the new royalty; some choose to act benevolently (Bill and Melinda Gates Foundation), hoping to improve the lives of others less fortunate. Others act as tyrants, ruining the lives of others out of fear, spite, or just because they have the resources (and lawyers) to do so . Our US government is stuffed with people who are already super-wealthy (by most Americans' standards) yet they peddle their influence to the highest bidders (Koch Brothers, Big Oil, Big Pharma, NRA) to do their bidding for them. Billionaires (and even multi-millionaires) have more money than they can spend on their practical needs, so to keep themselves on top, they use their money and influence to keep others down. If they're black, keep them in the inner cities and let drugs and crime run rampant...if they don't destroy themselves, we'll send in the police...Keep the Native Americans on the poorest land possible so they can't even feed themselves. Hispanics? If you can't deport them all, at least build some rediculous wall to keep the rest of them out.

The allure of becoming a drug kingpin isn't that you can supply all of your friends with the drugs that you've made them addicted to, it's the money you make (and all of the things that come with it). Drug dealers are by no means stupid or lazy, and would probably be clever enough to grow a successful "legitimate" business, except that they aren't presented with the opportunity. Many downtrodden groups in the past have made their fortunes illegally, and a few have even emerged to give the appearance of having made their "American Dream".

Thanks for sticking with me so far...

As for the original question: Yes, all lives matter...but even more than that, I believe that all CULTURES matter. Diversity is what makes this country strong (if sometimes not 'great'...), and without thoughtful leaders from all races and origins, that strength is diminished....

(( Something else to be considered: 'All lives matter' includes causasians as well, which I think is sometimes overlooked. Not every white man is rich, just as not every black man is poor. ))

Who told you that not all lives matter, and what was their argument?

My life matters and my dogs.this is my world you are all breathing my air.get off my mountain!

All life matters

Depends on how you look at it...

I think the recent issues with "all lives matter" is because of the adoption of that term by white nationalists in an attempt to counter/mock the Black Lives Matter movement.
Which was created to voice the general unrest of black citizens who feel that are underheard and under represented. And rightfully so. Black people have been treated poorly in this nation for generations and, lets be honest... All across the world.

The BLM movement became strong during the (thanks to social media) highly publicized police brutality that is subsequently swept under the rug by city officials. Nevermind the face that many of these cases resulted in deadly force that would be and has been deemed unnecessary and an abuse of power by officials in other nations.
BLM gained a lot of steam and eventually ALM emerged. Completely over looking the point of BLM. Proving the underheard and under represented claims.

BLM was never about saying "Black Lives are more important" which many people believe that's what it means. It is literally about "Hey! We're people too. Stop treating us like shit."

As for the "No lives matter"
That surfaced because of passive people who just want to ignore what's going on and that's the way they passive aggressively dismiss the issues.