The meme is unclear
It is not clear whether the meme is talking about absolute numbers or per capita murder rates. I'll talk about both.
The meme does not distinguish murder vs homicide
The first thing to note is that murder is a legal term, not equivalent to homicide. Murder does not include accidents or various manslaughter that led to homicide without malicious intent. In short, murder ⊂ homicide. The distinction isn't made in the meme.
For simplicity, I'll focus on murders only.
The intentions of the meme creator is politically-driven and fallacious
People who made the meme and who are spreading it are attempting to impress the concept that liberal-run cities with strict gun laws actually result in higher than average murder rates without providing additional substantive context, and thus committing a correlation fallacy, non causa pro causa.
Their point is that gun laws don't stop violent crime, as a means to maintain popular support for ownership of firearms, but they don't bother to analyze what percentage of the crime is committed with a gun, nor do they simulate what the violent crime rates would be if those laws were not in place.
The data do not support the meme
Putting this aside, the statistics simply don't support the assertion.
||~ 18.23 per 100,000 
||~ 40.31 per 100,000
||~ 23.96 per 100,000 
|4. St. Louis
||≤ 194 
||~ 62.95 per 100,000
|5. New Orleans
||~ 30.95 per 100,000
||16,425 [2019, FBI]
||328,240,000 [2019, World Bank]
||~ 5.005 per 100,000
|U.S. ( – 5 cities)
||~ 4.693 per 100,000
So removing those 5 cities does impact the murder rate nationwide, but not as significantly as the meme framers are professing.
In the fairyland tale where the U.S. doesn't have the five cities, it might be better than Kenya or Angola, but other than that, there is no noticeable improvement in terms of world rankings or whatever: