Darrin wasn't abusive but he was stupidly fearful of Samantha's powers being discovered to the extent he didn't want her using them at all. I think Tony and Jeannie got a better balance with that from their show's writers so Bewitched didn't need to make Darrin so paranoid. However, when it came to Tabitha, he was absolutely wrong. She's got those powers and abilities. She needs to learn how to use them properly otherwise it is leaving a kid with a loaded gun so to speak. It's also teaching her she is inherently bad because what she is, a witch, must be suppressed and hidden. Darrin is being an ass on this score. Sure, a lot of Sam's relatives were no boxes of peaches but his attitudes didn't help him win anyone over. Tabitha needs Sam and her witch relatives so she can grow up without a sense of shame for her being a witch instilled in her by her father's paranoia.