All LCD (and "LED") monitors suffer from some degree of backlight bleeding. It is a design / technological limitation that you simply must live with and hopefully the backlight bleeding is so slight that you do not notice it. It's kinda like saying a CRT monitor is big, heavy, and power hungry because of it's design / technological limitation.
As pointed out by 474554b, when the monitor is on the backlight is always on as well. Even when the monitor is displaying black the backlight is still on. Traditional LCD monitors uses CCFL (florescent) lamps and they are placed directly behind the LCD panel. This is referred to as a full array backlight. Inexpensive monitors can have a few a 2 CCFL lamps while more expensive ones can have as many as 7 CCFL lamps which helps with uniformity. That is the distribution of light across the entire screen, the more uniformity the less likely you will notice some parts of monitor being slightly brighter than other parts.
"LED" monitors are simply LCD monitors with LED backlight. The difference is the LEDs are not place directly behind the LCD panel. They are placed around the edges which is why they were originally advertised as edge lit monitors. This reduces the weight, thickness and power consumption. However, you may notice more backlight bleeding around the edges because it is not a tight fit.
Backlight bleeding does not harm the monitor in anyway. However, depending on how much bleeding there is, you may find it annoying.
The above also applies to LCD or "LED" HDTVs. But does not applies to plasma HDTVs since that is a different technology.