why does egeus prefer demetrius to lysander

The text does not tell us why Egeus prefers Demetrius over Lysander. We can only infer or speculate. We might consider that Demetrius had asked Egeus already for his daughter's hand before Lysander got around to wooing Hermia. Father's felt their daughters were more or less their property until they were married off.

the reson is simple: egeus is from a noble family and so is hermia but lysander is not much of a noble man than demetrius. secondly if u read further chapters where lysander is put under a love spell, there he calls hermia an ethiop, a dark person which shocks her deeply as she is dark and so is demetrius for when oberon puts him under the same spell he in his first praise for helena describes himself as a crow and helena as air. thus lysander and elena are white while the other 2 are darker compared to the others. this also brings out that class of respect differed during that era