Not as many as you might think, Jeff. There are no ghettos in this country (in the real definition of the word.) There are certainly blighted areas, neglected areas, ethnically concentrated areas, but no ghettos.
And it’s not the word “ghetto” itself that is objectionable. (See the definition below.) It’s the context in which it is used that creates the problem. (See definition #4.) The usage here by Trump is meant to imply that the preponderance of black Americans are living in squalid, run-down, crime-ridden, and living in a state of hopelessness. We aren’t.
The fact is, most black Americans are not even living in cities.