It makes perfect sense. Since you are restricting yourself of certain foods, you are also not getting certain vitamins and minerals that are necessary for your body to function correctly. And before you say it, vitamins and minerals you obtain from food are 100% better than the vitamins and minerals you can get from a supplement.
I have never followed a Candida diet 100%. They are way too strict, and you set yourself up for failure because when you cheat (and everyone cheats at some point) they immediately think they have destroyed everything they've worked for. This kind of pressure and negative reinforcement is not necessary.
I only cut out three things from my diet after I was diagnosed with Candida. One of those was bread (or anything else containing yeast). The second was mushrooms (as they are a fungus). And the third was all alcohol.
I still eat most fruits (pineapples, apples, and coconuts are my favorite), most vegetables (the ones I like anyway), all meats and seafood, some grains (such as oatmeal or museli), and some dairy (such as yogurt and goat's milk). I cut back on sweets, but sometimes I still have ice cream (it's my favorite). I also eat some nuts and seeds, such as pumpkin seeds, cashews, sunflower seeds, etc.
The point is, I eat a lot of things that some Candida diets will tell you are off limits, and I'm still fine. I was diagnosed and treated for Candida a little over two years ago, and since I was treated I haven't had a recurrence of it.
By the way, I also take a probiotic supplement everyday, I eat plain natural yogurt with live active cultures everyday, and I rotate between virgin coconut oil, cinnamon, and green tea as they all have anti fungal/antimicrobial properties.