That is simply a proposed reroute. Those do not always make sense from an individual's point of view.
You should do the research to determine the flights which best suit you and ask to be rerouted in that manner. Have flight numbers handy. Give consideration first to IB, then BA, then OW. In particular consider BOS-LHR-ATH on BA (or AA for the first segment) as BA operates four daily nonstops LHR-ATH.