If one must make a blessing before eating because if not it is gezel, if a person supposes that he made a blessing, safek beracha lehakel, Why is it not considered safek gezel that is prayed and the blessing is made?
Thank you for your question.
The reason why we make a bracha before eating is because we have to thank Hashem for the food that He gave us. What you are referring to is the Talmud Brachos 35b that a person who eats without saying a bracha is as if he stole from Hashem and Klal Yisroel. Rashi explains that it doesn’t mean that he actually stole, rather that by his abstaining from reciting the bracha he is inhibiting Hashem and Klal Yisroel from what they could have benefited. Hashem “lost out” because the person denied Hashem His blessing, and Klal Yisroel loses out because, when a person makes a bracha it causes bounty and bracha from heaven. When a person doesn’t say the bracha this benefit is denied to Klal Yisroel. The gemora does not mean that it is actual gezel, in the sense that the person committed the prohibition of “Lo Tigzol”, rather as explained.
Additionally, the obligation to make brachos goes according to the halachos that chazal have given us, and since they said that in this situation we should not say a bracha, it would not be considered denying anyone what it coming to them.