Why is the translation "why are you searching for this horse?" not accepted.
Should be - report it.
A good english equivalent of "szukacie" is "seeking" because it doesn't need a proposition - "why are you seeking this horse?"
We usually accept it, but somehow it was missed here. Added now.
Where is the distinction made between "Why are you looking for this horse" and "Why are you looking at this horse"
Polish uses totally different verbs for those. From our point of view it's kinda strange that "looking for" has "looking" in it.
"Why are you looking at this horse?" is "Dlaczego patrzysz na tego konia?".
What about "why do you search this horse" ?
That's a different verb. "to search someone/some place" is "przeszukiwać", so "Dlaczego przeszukujecie tego konia?".
Oh no...