Because it is still a living thing. Respect the MJ dude, it treats you pretty well. Would you want to be euthanized just for having a penis?
And who knows, maybe it will pollinate a female out there and in 5 years, you will have a field of natural marijuana plants.
As far as your setup and veg and flowering. This will be REALLLY brief because I have work in like an hour
You have your light, it needs to be on a timer. the two most common light schedules are 12/12 and 18/6.
These correspond to the different life cycles of the plant. 18/6 is for the vegetative stage of the plant where it starts out in its life cycle. This stage is for node growth and is important for high yields.
12/12 is the light cycle that corresponds to the flowering stage of the plant. This is the stage where you get your buds and seeds if applicable. When you switch to 12/12, the plant thinks that fall is starting(Shorter days) and it goes into reproduction mode. This is where the THC in the females really starts to be produced. THC as far as I have read is only meant for male pollen to stick to. It just happens to be the psychoactive substance(among many others) that we use to get medicated.
When you switch to 12/12 you will see a few things. First, you will see stretching of your plant.(Not sure why, someone chime in please) Second you will see your first preflowers at all the node sites on the plant. Preflowers can be male or female and this is the most surefire way to tell the difference between them.
This is something that you are going to have to experience for yourself but a male flower looks like a banana. a female flower looks like a seed that has two white hairs coming out of it.
I don't remember the rest of your question, but I am off to work.
Peace & Pot Errbody!