You can't trick me, Fitpregnancy! I know you're sitting there laughing at me because I'm pregnant and desperate for cold sweet things and will believe almost anything you say because you have the word "fit" in your name!
Oh, really? I have older brothers, I'm not falling for "this will make you seem grown-up" this time. It worked with the peppers in Chinese food, straight vanilla extract, and Black Russians, but I've since wised up. Nice try with the "decadent" though.
Look, I get that people who read that website (myself included) are there trying to find healthy and clever ways to trick their body into thinking nothing's changed ("No, no, this drink is totally the same as a whiskey sours— see how it's in a special glass? And when you want a doughnut just put cinnamon on a whole-wheat English muffin. Works like a charm! Being pregnant is fabulous and the sacrifices are delicious!!!!!!!") but let's not play on their vulnerability here.
Have your ice cream. It's hot. Eat healthily the rest of the day and indulge in this one thing. Put olive oil on something else (suggestions: bread, broccoli, popcorn, fish). Drink it plain for all I care; it's good! And go ahead and sprinkle the rest of those toppings on your delicious, non-oily ice cream. The sea salt and pistachios sound like really good additions, actually. I doubt I'll even mind that I don't have chocolate sauce.