The original question, as asked, lacks context and so isn't a valid question. Today, the term "generic fantasy" and "Tolkien rip-off" mean practicaly the same thing. But Tolkien's fantasy isn't generic; no moreso than Howard"s Conan/Kull, Leiber's Fafhrd & Grey Mouser or Norton's Witch World et. al..
Therefore, the question becomes, "How is Glorantha not a Tolkien rip-off"? I would think even a casual perusal of both worlds would answer that question (and if not, has already been well answered by others already).
Now, both works are fictional and both works are fantasy. In that regard, they share some of the tropes of the genre which you could find comparing any two fictional fantasy works; gaming or otherwise. But if you're going to go that deep you might as well claim that all fantasy worlds are, effectively, the same which just leads to circular semantic discussions of little value.
"Exotic" in terms of fantasy literature and/or gaming nowadays is far too loaded a word to carry much meaning or weight.
jolt