I am not sure the authors have ever been to Boston. Here there is only Inbound and Outbound. I went to www.mbta.ninja and then spent about 30 seconds trying to figure out if any of the alerts are related to me.
We are definitely trying to make the line selection easier to use, so if you have ideas it would be great if you could make a Github issue!
If you want to talk about the Red Line delays going toward Alewife, then inbound or outbound is uselessly ambiguous.
Of course, they could ask you to input a station first, then display the connecting lines as inbound/outbound.
Directionality (for new folks) or terminus (for more seasoned riders) are infinitely better than Inbound/Outbound.