In its traditional sense, endear means to make dear, with its direct object making itself dear to its indirect object. For example, I might endear myself (direct object) to you (indirect object) with this post if you find it useful, or you might endear yourself (direct object) to me (indirect object) by posting a comment expressing your thanks.
If we give most credence to the standard dictionary definition—which isn’t always the best approach, but we’ll do so here for the sake of argument—then endear is misused when its direct object is the person or thing being charmed—for example:
As usual, the episode lacks a proper sense of dramatic development, while failing to endear us to the walk-on characters at the center of it all. [Mania]
[W]hat Allan McCormick … noticed on arrival in the afternoon didn’t really endear him to the famed Indian hospitality. [Hindustan Times]
In both of these examples, the direct and indirect objects have been reversed. In the first, we can infer that the walk-on characters are actually endeared to us. In the second, we can infer that the famed Indian hospitality is actually endeared to him.
These are less questionable because they use endear to mean make dear:
None of that is likely to endear him to conservative voters in the district. [Denver Post]
While Angle’s comments likely won’t endear her to the Republican establishment, they could conceivably enhance her street cred with the sort of Tea Party voters who have helped power her efforts so far. [NPR]
His passion for the work of Habitat and his uplifting stories endear him to many, and he has an amazing talent for igniting similar passion in others. [Citizen Times]