If they said their WebOs team, ie., Jio Cinema's employees working with WebOS, it should be true...
If not then, that is not correct.. WebOS is an OS similar to Android TV, its not like LG or Samsung for that matter on Tizen are blocking Jio Cinema's progress.
If that's the excuse, then how are Netflix, Amazon Prime Video, Disney+ Hotstar and even Sun Nxt have far more competent apps on those respective Operating Systems?