I'd make two(or maybe 3) points in response to your post:
1. Nutrition is definitely an indiviual thing - and there is no one diet/nutritional plan that works for everyone - be it because of religious restrictions on food, intolerances, or simply not liking certain foods.
2. While many on PB do go low-carb, it's not a *requirement* - though many on these boards feel that lower-carbohydrate diets had the best results in terms of achieving the goals they wanted. Sweet potatoes are considered perfectly normal within the PB - not the best option if lower carbohydrates are your goal, but a good choice if they fit with what you're trying to do nutritionally. White rice is one of those "marginal" foods - technically not the most primal of foods, but a relatively clean carbohydrate choice, and better than most if you want to use it as a carbohydrate source.
3. There's no rule that says "YOU MUST EAT THIS WAY" - if there are certain details within a diet that don't fit for you, you can try modifying it to suit your needs and see how that works. It may not be by the book, but there's nothing inherently wrong with that. In general, eating as many minimally-processed foods as possible should be good for you, even if you like to have the periodic helping of rice(which again, if not primal and a bit high-GI, is still a pretty clean carb).