Here's a scenario demonstrating the idea:
Let's say I spend $92,300 to buy 61 shares of TSLA at its current price of $1,512.18. Then I post my Tweet causing TSLA to jump to $1600.00 on the same day and sell my 61 for $97,600. My total profit is only $5,300.
But what if instead I buy $92,300 of 7/17 TSLA call options at $1600? They cost only $9.23 per contract for 10,000 contracts. Now the same price movement to $1,600.00 today causes the value of my options to increase to $39.16 per contact. I can sell them for $391,600 netting me a total of $299,300 for the same starting capital. If you have access to margin then you're talking millions in profit with even a small price movement (though at that point you probably have to start worrying about the SEC).
In general though I agree with you - I think a person absolutely could make more than $100k on the market with not a lot of capital and get away with it.
Of course, "not a lot of capital" is still more than no capital.
Watch stock go up, sell before the whole thing is clarified.