Financial sector aghast the poors are gaming system designed to be gamed by the rich

It a reference to an old fable.
A scorpion, which cannot swim, asks a frog to carry it across a river on the frog's back. The frog hesitates, afraid of being stung by the scorpion, but the scorpion argues that if it did that, they would both drown. The frog considers this argument sensible and agrees to transport the scorpion. Midway across the river, the scorpion stings the frog anyway, dooming them both. The dying frog asks the scorpion why it stung despite knowing the consequence, to which the scorpion replies: "I couldn't help it. It's in my nature.

In this case redditors (the scorpion) laugh because they actually have nothing to lose (except an initial investment) while the frog (wall street) whines an economy crash will hurt all (in 2008 the bankers walked away unscathed).