yeah, its hard to keep a black car in showroom condition, especially if you're driving it around.
so you said you took a towel to wipe off the dirt and mud....you didn't do that dry did you. if that dirt and mud was any larger than say...dust? you may have causes the microscratches yourself. i would have given it a proper cleaning/wash if it was as dirty as i imagine.
im not trying to blame you for anything here, just trying to make you cognizant of the fact that black cars are SO easy to put swirls and mini scratches on...and they definitely show up. just keep the car clean and use plenty of wax
also, just accept that small dings and scratches will happen; if its a daily driver, its bound to happen. it just builds character and shows you aren't a ninny with your car.