The same reason they aren't evolving into lizards or penguins...human traits work for humans, ape traits work for apes, penguin traits work for penguins. Get it? What benefit would apes get from walking on two legs and losing all their hair? It would be harder for them to walk and for young apes to cling to their mothers.

The exact motives for why humans evolved the way they did are still debated by scientists. There's universal consensus in the field that human evolution did happen (except for a few fringe "researchers" trying to prove that the Bible is literal fact and God did indeed put dinosaur fossils here to fuck with our heads), but the exact circumstances behind the evolution isn't known for sure. There are many interesting interpretations of the evidence, like the aquatic ape hypothesis that humans were semi-aquatic animals at some point.

Humans have plenty of features which are totally useless for us but which are useful in animals related to us. For example, the cebaceous glands meant to keep fur slick now do nothing and just cause problems for us since they are the cause of acne. We have a tailbone, but we don't have a tail anymore. And pinky toes...other primates can use theirs for grabbing and such but in humans they do absolutely nothing for us.

And the number one evidence for evolution....FOSSILS! If you reject evolution and don't want to put forth the claim that God is just fucking with our heads, then homo sapiens and homo erectus and homo habilis and homo australopithecus and homo neanderthalensis must have all lived contemporarily with each other (and with pterodactyls and brontosauri and trilobytes) AND were all able to maintain their populations despite all the competition from the other species, even though carbon dating shows them to be from separate periods in time and you have no explanation why all those other homo species aren't around anymore. I find that hardly believable.