As mentioned above, host or hostess has absolutely no sexual connotation in AmE. In fact, the word is so far removed from sex that guide books for American tourists traveling to Japan and other Asian countries make specific mention that a "hostess club" is
not a pleasant family bistro with a friendly greeter, but a place where men pay women for sex. Likewise, sometimes naive young non-native women accept "hostess" jobs in Japan or Korea thinking they'll be taking reservations and seating people in a restaurant only to find out they've signed on to be a prostitute.
Probably because it sounds more socially acceptable than "prostitute." Same reason, for example, a
stripper might describe herself instead as an "exotic dancer", or a place that sells nothing but pornographic magazines calls itself an "adult book store."