Because its fun.
Because you can.

I've been running critCho from lvl 20 to ranked games, and even when my teams sucked, i still came out positive.

Force of Nature can be replaced with a Thornmail, depending on enemy team comp.

Go mid if no one else will, go top if you have a jungler
Basically, get your own lane so you have free reign over last hitting.

Cho is a resilient mofo in a lane due to his passive.
if you aren't a complete failure you should last hit EVERY MINION
(since this ****ty game has no deny mechanic, this should be easy)
If you last hit everything, any early game harassment means nothing therefore you can simply ignore the champ doing dmg to you.

Rupture: get it 1st in case you need to get away from a lvl1 gank or assist in one.
and since you are not going AP, you don't need to level it

Scream: use it for utility and escape prevention. (ex:if a champ is running towards you, its most likely going to cast on you... so silence it)

Spikes: your main skill since it adds a good ammnt of damage early, it makes last hitting easy, and it keeps mele champs at bay

Feast: use it as soon as it is off cd if you don't have full 6 stacks
eat champs, acquire currency.

PRO:
-most people ignore you since you are the "tank" giving you time to shred trough their squishies
-with 5000+ hp Atmas gives you at least 100 dmg
-you can be a HPtank, do AD, and AP spike ppl with your Feast

CON:
-kogmaw and other champs that do 2%HP will eat you (unless you are competent with your knock up)
-you will never be as tanky as your team expects you to be

every build I've seen had either tank, AP and APTank so i decided to put mine up.

i could care less of what anyone thinks of it, since i run it and been doing amazing with it since i started.
If you don't find any success with this build, srry, qq and go find another.