Still confused by what's in the background but great story.

I think it is purple potatoes (yes, a real thing), surrounded by green peppers, yellow squash, and tomatoes.

Yep that's what they are.

I believe the person is not so much confused by the fruit but by why its there :o
Its there because the post is about being gay, and having a fruit platter behind it makes a visual pun because being gay is also referred to as 'fruity'.

Although insightful, Kitty, I think it is just a picture of food because the conversation was "at dinner."

Purple potato? Maybe you mean yam? Or taro?

Nope, I mean purple potato. https://www.google.com/search?q=purple+potatoes&espv=2&biw=1920&bih=947&source=lnms&tbm=isch&sa=X&ei=2K9GVZPdIfO1sQT4_4CYBw&ved=0CAYQ_AUoAQ

But it's a FRUIT platter... And it makes a rainbow... Just an observation. I didn't put it there

Actually, it's not. My original guess was correct, except for the addition of orange bell pepper. Check out the recipe I found for this pic http://www.thedailymeal.com/rainbow-pizza