Translation:I do not like triangles because I do not like mathematics.
Obviously! It wasn't that I didn't know that triangles are connected with geometry.
The sentence as a whole is constructed to show a negativity towards mathematics. I was asking why the Duolingo people chose to do this?
"The Deity ever geometrises" as Plato is said to have expressed it, gives a more accurate view of geometry.
I’m sure that you did know it — I was attempting humor on the basis of circular logic (if you’ll forgive that pun), i.e. “because triangles are evil by definition, mathematics must be too, because mathematics are full of triangles”.
My own educational background is in mathematics, but it’s not hard to imagine that a random person could hold a negative view of mathematics. Don’t take any sentence here as representing some sort of universal axiom that’s held by the course creators.