If something is reviled, you alone don’t dislike it; a whole community of like-minded souls has to hate its guts. For instance, spam is widely reviled. (The junk e-mails, not the potted meat. Somebody out there really does like that potted meat.)
If you’re the only one who hates, say, your math teacher, it’s not fair to say that person is reviled. If she is majestically unpopular with the entire senior class and is routinely the butt of geometry-themed insults, well then sadly, this instructor is indeed reviled. Generally, when someone or something is reviled, much of the poison aimed is in print, such as critical reviews or insulting editorials.