This is part of why so many games on a competitive level end in a draw; the player that lacks a path to victory will try to force a stalemate.

Since this makes it harder for the player with an early advantage to win (by constraining their moves), it is considered a feature, not a bug.

I think it's because the rules of chess don't state that making a move that puts yourself in checkmate results in a loss, they state that you're straight up not allowed to make that move. So if the only moves you have left would put you in checkmate, they're not legal moves.