למה "לי", לא "אותי"?
Because the verb עזר in Hebrew comes with the preposition ל to indicate the person being helped.
is helpful to me would maybe be a more direct translation.
I disagree. עוזר ל is simply "helping". It's a verb, not an adjective like "helpful". It's a direct translation, it's just the usage of the verb changes between languages.
You're right but some people may find it helpful to remember it that way. You also have the verb כועס which translates to is mad where mad is also not a verb but an adjective. :)
Can someone explain why it is הסוס עוזר לי and not הסוס עוזר אותי?
AlmogL had already answered that question in this thread long before you asked it.
duolingo's world is a zoo, so far no human beings help..... ; )
ha-sus ozér li.
ולמה עוזרת? כתוב סוס