What does Doolittle not object to about the requirements in Wannafeller’s will and what does he object to? (Act 5)

From the text:

Them words is in his blooming will, in which, Henry Higgins, thanks to your silly joking, he leaves me a share in his Pre-digested Cheese Trust worth three thousand a year on condition that I lecture for his Wannafeller Moral Reform World League as often as they ask me up to six times a year.

It ain’t the lecturing I mind. I’ll lecture them blue in the face, I will, and not turn a hair. It’s making a gentleman of me that I object to. Who asked him to make a gentleman of me? I was happy. I was free.