Obviously, anyone that wants to ignore any aspect of all this is free to do so -- but I think you're missing out on part of what makes Orks...well...Orks.
Imagine their frustration, trying to make it in a public school system. Being physically mature, but not quite mentally mature yet, and how dangerous it would be for a middle-school aged Ork to get in a schoolyard tussle with another kid (over metaracial slurs or what-have-you). Imagine trying to keep a grown-man's strength in check all day, crammed into a school uniform, dealing with average human ten year olds, getting fed the same portions as them, expected to sit in the same desks. You struggle through school and your mind catches up to your head; then what, college? A job? It's about time; by the time you've got your foot in the door with an entry-level position, your life is almost half up. Imagine not being allowed to legally vote, or drive, or drink alcohol until you're soundly middle aged. Imagine the resentment towards Humans, Dwarves, and Elves -- society tells you they're all smarter than you, society tells you they're all better looking than you, everyone knows they'll all live longer than you (especially the non-Humans). You know you'll never last long enough to get that middle management position, because that smug Elven bitch you work for is going to be here for hundreds of years, and you feel like you've barely got hundreds of days.
Then your wife gets pregnant. Six kids. Six, and you've got to put food into each and every one of their hungry mouths. They're growing like weeds, just as fast as you did, and they're going through clothes so fast, and food, and breaking their toys...and your bitch of a boss wrote you up for using company electronics for personal use last week, but you had to go to this conference call because Johnny broke some runty Human kid's arm, and between that and him starting to bust out Or'zet like those damned rappers, the executives of the corporate school district want to expel him, and you just lost your vacation for the year over it but they're growing up so fast and you just feel so worn down and old, when will you ever get to see them again?
And on, and on, and on like that. And those are the ones that try to work within the system. The ones lucky enough to have SINs, and the ones who follow the rules. You want to know why the Orkish ganger is a cliche? Because it makes sense. Stronger and tougher than a normal human, growing up faster, maybe not the brightest bulb in the lamp? Breed like crazy, have trouble staying in school, feel frustrated and held up by society's laws (that never seem to take metaspecies into account), so the inner cities are full of them?
Hell yeah, Orkish gangers grow on trees. Look at their alternatives.