Hey guys. im new to Crypto-Money and started to invest and mining several weeks ago.

Everywhere on the Internet they tell that starting to mine in 2017 isnt profitable anymore...
Actually i can mine with my 4 RX470 100MH/s ... thats a monthly profit of around 150 USD (calculated with electricity price)
So why is it "not profitable" ? in 6 Month i have the money i spent back and after that point its profit. For passive income not bad i think.

Can someone of you explain this "not profitable" arguments?