Actually ‘cinemagraph’ had no definition before. Cinema did, and so did graph; but the combination didn’t, and just like every other new word that has been created by blending two words together, this is a perfectly acceptable and correct method for producing a new word. The word would be redundant if it simply meant “loop” or “filmloop” as you claim, but it doesn’t, it means something more specific. Words that are more specific are useful, providing they’re used correctly, because they don’t need further description to convey a precise meaning.
This argument doesn’t actually reflect negatively on the people using the word cinemagraph (correctly), it reflects badly on you for not understanding etymology; which would be fine, except that you’re arguing in a petty, offensive and aggressive manner.
