white plays b5 threatening your knight, if you take d4 then white takes with the queen (i assume it’s there), so you either have to retreat with the knight (wasting 2 turns) or lose it.

E5 is good because it opens an attack on the b pawn with the black square bishop, and if you do take it you get a free check which only defenses that are kind of awkward/passive. protecting the b pawn is also a little weird, the engine thinks the best move for white is a3, which doesn’t do much to take control of the center or develop any pieces. White could take the e pawn but that’s just trading pawns and the end result is that black has a developed bishop and a better pawn structure.