It's been ~6 years since I've been but it was a little rundown. It is in an urban area and there tended to be groups of teens hanging around. We went with our older teens but not sure how comfortable I would have been with young children.
I don't think I've heard very many good things about it. I would choose Hershey or Kings Dominion or Busch Gardens.
"Urban area" is that code for there are a lot of black people there? Upper Marlboro is a very affluent suburb/exurb of DC, certainly not urban at all. I've seen groups of teenagers at every amusement park I've ever been to, unless it's someplace for little kids like Dutch Wonderland or Sesame Place. Why would that make one uncomfortable. The ones at Six Flags America are as well behaved as any other place.
OP, it's no Disneyworld, not as bright and shiny, and it's mostly rides and waterslides. On the other hand, it costs a lot less and it almost never has lines longer than 5 minutes. We go often and always have a good time.
Perhaps the poster was thinking of the Six Flags in NJ, because that is frequently how I hear it referred to & often the same complaint. I've not heard good things about Six Flags in NJ or MA.
I am going tomorrow so I'll let you know. Tickets are not cheap though can buy online for 29.99 each.
I knew that no matter how I worded it, it would be taken the wrong way. I tried to chose my words carefully. I can't remember the race of the teens but I felt like they were thugs and gang like. I won't go back.
Here are some reviews on Trip Advisor.

