The "I" does not refer to Paul but was used to represent those who eat meat with thankfulness. AT: "If a person partakes," or "when a person eats"
## with gratitude ##
Possible meanings are 1) "with a feeling of appreciation or thankfulness to God." or 2) "with a feeling of appreciation or thankfulness to the host."
## why am I vilified for that for which I gave thanks? ##
"why are you vilifying me when I was thankful for the food?". AT: "I will not permit someone else to condemn me." (See: [[rc://en/ta/man/translate/figs-rquestion]])