What group of people is losing the most money on the stock market?

we have a saying in the markets.
"Bulls make money. Bears make money. Pigs get slaughtered "

What does it mean?
People who  sit on the side lines just watch the market as a hobby and enter in them market when there is extreme enthusiasm tend to lose the most.

Scenario:

Steve to Jerry: Hey Jerry, have you invested in the markets. The markets have rallied 10% in the last 2 months.
Jerry: No Steve, I invested few years back. I had handsome profits. Never booked profits. Then when the markets crashed, I lost all the gain and little more. So i have decided not to invest.
Steve: I think i will invest this time if it falls by 5% from here.
Steve: Did you see the markets, it is not coming down, i kept on waiting. It has risen 10% since we last spoke.
Jerry:: Is it? I didnt even see the market. I am tempted now. Lets buy when it comes down by 10%.
Steve:: Jerry, did you see? We spoke last month, the market is up another 5% from there. I invested my savings yesterday, no point waiting.
Jerry:: Is it? now that you have got it, I think I will buy too.
BOOM!!!!

It goes up for few days and then everything starts falling.

But there is no plan to EXIT. Steve and Jerry dont need the money RIGHT now. They can HOLD. BOOM, another fall.

The point is, If you want to invest, decide about a stock. See the fundamentals. See the technicals.  If you dont understand, hire an advisory. Track it. decide on a level to buy. If it comes there, BUY.