Here it is. The most outrageous example of black privilege in history

[Emily]

because I know that scientists have thoroughly investigated and rejected that hypothesis.

What you 'know' is precisely the opposite of what scientists have found to be so.

That was the intent of those slogans and you know it.

I know no such thing and don't believe the intent of those slogans was in any was negative. They were intended to be healing and embracing. Marxists, who want to stoke racial animus as a tool to tear down society, along with some black dupes and professional race-baiters, advanced the ridiculous notion that saying that everyone's life matters is 'racist' and offensive.

Otherwise why did no one assert those slogans before others started asserting that Black lives matter too?

Because before blacks started stating something obvious no one felt the need to state the other obvious things.

Black Lives Matter means that cops' lives do not matter, so Blue Lives Matter does mean Blackist lowlifes do not matter.

You're posting in your usual style (which I enjoy quite a bit) but the actual fact is that neither of your clauses is correct.

Cops defend themselves when threatened, sometimes with lethal force. Race isn't a consideration in the confrontation. Some chose to make a racial issue of it, as some choose to make a racial issue of everything. It isn't.