Provide blessings upon burning the Etrog

Hello Rabbi,
Regarding this Halacha:
 
A) One who takes an etrog to smell it throughout the year recites the blessing, "Blessed are you, G-d, the One who gives a good smell in fruits," which is the wording of the blessing of smell over fruits that are fit to be eaten. 
 
B) An etrog of a mitzvah during the days of the holiday, and a person was taken to smell it, they disagreed about whether to recite the blessing of smell over it, because some say that during these days it is not defined as being ready to smell (since it is ready to perform a mitzvah). And in order not to enter into this controversy, the Shulchan writes that it is correct not to smell the etrog of a mitzvah during the days of the holiday [Emphasis: The very fact that the etrog is used for a mitzvah does not prohibit smelling it (see below in the introduction to the extended answer), and therefore, the avoidance of smelling it does not stem from the fact that it is used for a mitzvah, but only from the fact that there is a disagreement as above regarding the blessing and we want to avoid it].    
 
c) However, on the Sabbath of the Feast of Sukkot, when the mitzvah is not being performed, there is no obstacle to taking an etrog and reciting the blessing of smell over it as usual ("He who gives a good smell in fruits", as above).
 
 
I wanted to ask you about the prohibition of smelling the etrog on Sukkot. Why don't we say doubt in blessings to ease up on this? After all, if we were to avoid all the things about which we have halachic doubts in the context of blessings, we would have to avoid a lot of foods (for example, rice crispies), but I don't know that there is any point in avoiding foods about which there is doubt in the blessing (at the bottom of the email, there is a halachic expansion on the subject).