Many of the SH readers (and authors) come from NU, and many of the translated Japanese isekai stories there follow that same old appearing in a forest, saving some girl from goblins/bandits or rescuing a fox girl/cat girl slave formulas, and people do read and translate them (some even receive donations). It kinda gives a false illusion of popularity and thus the new writers try to follow the same formula, hoping that their story would also be well received.
...and there is also wish fulfillment, nothing can be done about that one.