Because I think "meat" is what those original fleshpots in Exodus referred to.
If only we had died by the hand of the LORD in the land of Egypt, when we sat by the fleshpots and ate our fill of bread... (Ex 16.3, NRSV)
In Hebrew it is two words, pots of the flesh,סִ֣יר הַבָּשָׂ֔ר (sir habbasar) and clearly followed by "ate our fill of bread". It is saying that we sat by the meat pots, the stew pots and ate our share of bread. It has nothing to do with sex, just that the Hebrew word for meat (basar) can also be translated, "flesh".
Still... if I passed an establishment with a flashing "FLESHPOT" sign, I'm not sure I would go in and order a beef stroganoff. The word seems to have acquired a life of its own.