Common misconception.
Out of Bellator’s top 10 PFP list, the first 6 out of 10 never even fought in the UFC and only 3 of 10 actually have. Plus many if not most of the UFC fighters who go to Bellator, do so with winning records in the UFC (e.g. Bader, Davis, Mousasi, Pettis (win over current UFC FW champ Moreno), etc.).
I’m not arguing Bellator doesn’t sign former UFC fighters, but it’s not like Bellator fighters haven’t gone to the UFC and done well, either.