Yeah, no, that's the Latest Leftist attempt to "seize" the word and make it positive.

Grooming is both done in a sexual way as u/acp_k2win specified, but also in an ideological way.

You shouldn't ever be trying to ideologically groom your kids. If you have values, principles, and traditions; you don't need to. If you teach your kids your values, you should not only be able to enforce them, but actually let the kids learn why your values exist as the way they are through their own experience. It is life that will shape their experiences and show that your principles and values have merit, not your attempts at ideological indoctrination that will only expose your own personal weakness in being able to refute challenges to your ideology, but to also promote resentment and blowback as a result of your attempts at indoctrination.

So, I'm Libertarian, and I lean towards anti-theism. I don't need to psychologically and emotionally condition my kid into not believing in God, nor do I need him to be conditioned into not believing in the state. I will enforce my values on him, but that's not grooming (it's him living in my family). I don't need to teach him to oppose religion. I can explain myself pretty succinctly regardless of which ideology I may lean on. Instead, if he meets a pastor, I will remind him that a pastor is not an arbiter of objective morality, and that he is another man with his own perceptions of morals, and instead can't be looked to as a sole authority on morality. If his best friend's dad is a cop, I'm not going to tell him to abandon his friend because cops are statists; I'm going to tell him that his friend's dad has a job which requires him to enforce the law at the behest of the state, and that you can't expect him to bail you out if you get in trouble. If he gets in trouble, he'll see that his friend's dad is not necessarily the first person to go to. If he has moral questions, he won't treat the pastor as absolute sage.

Your ideology are just useful models that can be applied, incompletely, to the world to help you make decisions. None of them are right, nor perfect. You should not teach your children that, and you should not accept it. You should instead instill your values in your children, but allow them to live life in such a way that they will gain experiences that can utilize those lessons or models.