Well DT, as TB points out, Vito did not express an objection to Sollozzo conducting his business and did not set any parameters on his doing so. Vito expressed his reasons for not agreeing to Sollozzo's requests and I don't see how we can question the words from his mouth.

I have never understood why Sollozzo would want to murder Vito if it was Vito's political and judicial help he was seeking. Sonny being "hot for my deal" does not rationalize Vito's murder either. Of course, that has been discussed extensively in other threads. But that undercuts the movies realism and logic. Perhaps it would have made more sense for Vito to have told Sollozzo that he should not operate in Corleone territories or that he would have used his power to oppose drug traffic. Now those would have been really good reasons for Sollozzo to go after Vito.