Doomsday would have caught it and shoved it up Batman's ass. Never to be found again.
My question is why not throw it to the chick that smiles when monsters hit her.
Why spoil her fun.

Lol, what? Kryptonite removes the powers of a Kryptonian. Aunt May could have thrusted that spear through Doomsday's body. If Superman had thrown it, it would have definitely penetrated Doomsday. And how is Doomsday going to knock it away when his arms are tied up by Wonder Woman? And if he does knock it away, YOU JUST PICK IT BACK UP AND TRY AGAIN. It's not a video game, where things disappear after you throw them. LOL The lengths people go to, to defend this movie.

That's the lazy script talking. If the script actually had Superman throwing the spear, it would have gone through Doomsday like butter. The only reason Superman struggles to get the spear through is because someone on the production realized how pointless it is not to have Superman throw the spear, and came up with the "his skin is too strong" bullsh!t to make it seem a little less idiotic.
If you can't defend a movie without bashing another, you will be put on ignore. No exceptions.

Thats a great explanation articappleman
No way he could've tossed that bad boy hard Enuff
I think Cavill and Snyder did that scene very well. I felt the weight of that spear along with superman
Another example of Snyders spectacular skill
The anti Troll Troll on a roll
gonna bowl over all the Trolls

Because it wouldn't have enough force to go through properly and there was a a chance doomsday could slap it away anyway, if you actually watched the scene you would notice superman fly's in and stabs him, then gets stabbed himself, he then has to push hard to get the spear to go completely into doomsday.