It's just another way of experiencing life. For many of us, the joy of exploring things this way isn't about removing the life or art from it; it's another way of witnessing and experiencing the life and art of it.
For example, I absolutely love aquascaping. I have a very scientific understanding and appreciation of it all, but it doesn't diminish how incredible and beautiful it all is for me. Some people look at it from a very aesthetic point of view, and to me it's often like some glorious chemistry and biology event occurring in front of me. I marvel at the fact that the nitrogen cycle is happening in this little slice of biotope. I love to test the water parameters and log what's been going in and out to better understand how it's working. I make nerdy little movies of the plants and animals. But you'd be hard-pressed to find someone who loves it significantly more, or finds it more beautiful in more meaningful ways. I just process it differently.
With the chili oil, understanding and experimenting with it can be part of how a more cerebral person engages with their appreciation, curiosity, or passion about the oil. Nerding out might just mean the person really loves it, and that's how they go about it. It's all good. Maybe they'll figure out a bad ass recipe that'll make the rounds eventually, and everyone can enjoy it.
Having hobbies is not only infantile but "hollow and sad"? Very strange take.
If it bothers you so much, don't engage with it. Taking time on a Sunday to write really nasty things about people sharing their hobbies on the internet doesn't seem especially full or joyful.
