Can't remove the male connector from the female connector, why is this so hard to remove
Not much to go on here. But, here we go, electrical connectors (assuming it's an electrical connector) can be difficult to remove. They generally have a tab or button that needs to either be pushed down (most common) or lifted up. If you look closely at the parts you should see the device that holds the two pieces together. It should then be obvious what you need to do to take them apart. Use a flashlight and/or a mirror if necessary. They all come apart, you just need to figure out how.
One thing, never, ever, ever pull on the wires. Always grab the plastic connector. Pulling wires can cause wires to stretch and break, at least.
Assuming this is the taillight connector (found with a quick google search):
There should be a tab that you have to either lift or a lever you need to depress. If the connector still won't come apart you could try some WD40 or contact cleaner to clear some corrosion that causes the metal parts of the connector to bind. After that it should come apart.
If this is not the connector it would be helpful if you included an image.