I'm not sure about Blake not being attracted to female MC, I just feel like he doesn't have much dialogue with the MC in general. You can't gain hearts with him yet.
To get hearts you need to complete specific events, to get the specific events you need to increase your ''like'' with them.
It's a bit outdated but you can still find some tutorials on most of the events with the main characters. https://docs.google.com/spreadsheets/d/1kk1nVwdcqxsqkysRpLgMoRE0wKDOmMXYfxKpDsBl...