Murders are bad. I'll wait for the facts to come in on these shootings before I comment on them specifically, because in virtually all of these shootings the original story changes significantly as time goes on.
I will say that it is pure myth this thought that cops are just going around shooting innocent black people. Obama today said that these shootings are not isolated. That is patently false. The chance of a black person being shot by a cop is incredibly low. The chance of an innocent black person being shot by a cop is even lower than that.
Blacks make up 12 -13% of the population and make up about 20ish% of police shootings. There's a discrepancy there obviously. But it's also important to point out that blacks make up about 40% of violent crime despite only being 12-13% of the population. That fact easily explains that discrepancy.
So, bottom line is murder is bad, but there is no systematic racism and these are absolutely isolated events.