The sweeter the juice

This morning, like most Sunday mornings, I headed to the Hollywood farmer's market. My fridge was already pretty well-stocked with stuff I hadn't managed to cook yet from last week's jaunt, but I needed a few more things, in particular, both some kind of vegetable for a side dish and some flowers to bring to this evening's seder over at R-ka's place to the northwest. The flowers and side-dish vegetable were easy enough to locate (the chard was deeply discounted in the last half hour of the market), and once purchased I could return from my goal-oriented shopping to a more general aesthetic appreciation of my surroundings. As I stopped by a stall where I often buy root vegetables, I was struck by the enormity of what lay before me -- specifically, giant beets. There were a few bunches with one mega-beet and the remainder normal, and one bunch with two mega-beets, so I decided to get that bunch and bring it along for the entertainment of R-ka's four year old. And maybe R-ka herself. My conversation with the farmer behind the table went something like this:

Me (English): Hi. How much are the beets today?
Him (Spanish)*: They're really big, aren't they? Two dollars.
Me (Eng): They are big. I don't know...
Him (Sp): You know, the bigger they are, the sweeter they are.
Me (Sp)**: Really? I believe the smaller, the sweeter.
Him (Sp): No, really. Here, check it out. (Cuts enormous beet into slices, cuts edges off one slice so no skin remains, and hands it to me to bite into. He himself bites into another slice with gusto. The beet is, in fact, remarkably sweet. Especially given that it is the size of a small watermelon.)
Me (Eng): Ok, I'll take this bunch.
Him (Sp): Thanks, Senorita. Have a nice day!

Up at R-ka's house, the beets were greeted with great excitement and immediately found a place of prominence on the kitchen table.
Mr. Fish, the four year old, thought he might use them for weight training, like dumbbells. The Survivor, R-ka's husband, immediately decided they resembled nothing so much as female secondary sex organs, and proceeded to put together a fruit-and-vegetable fertility goddess. (With matzoh shoes, which don't seem very worshippable at all, although what do I know.)
When I related my morning conversation with the farmer who had sold me the beets, Mr. Survivor said, "Wait, so he told you 'the bigger they are, the sweeter?' Are you sure he meant the beets?" And then gave an unholy chuckle.

Meanwhile, my question is, why, when I buy enormous vegetables simply because they are so very huge, do people always relate them immediately to human primary or secondary sex organs? A beet is not a breast. And a carrot is not a penis. As Sigmund might say, sometimes a big vegetable is just a big vegetable. Or am I deluding myself?

*This guy, for whatever reason, never talks to me in English, even though I very very rarely respond in Spanish
**If I controlled the past tense in Spanish, and also had a sense of how to convey imperfect aspect, I would have said something more along the lines of "I always have believed that..." So much for verbal nuance at the market.