I think it is important that children have the right to choose their relationships and I don’t think anyone should be forced to do things they are uncomfortable doing.
If you want to encourage more tactile affection, which can be important for child development and even adult relationships, you could model it. If you’re comfortable hugging certain people (or cheek-kissing, depending on your culture), your children probably will be. And if they aren’t, they have the right to feel uncomfortable and you wait until they warm up.
Even with dogs, trainers do not recommend just forcing them to be pet. You have to help them associate humans with positivity and happiness (such as through treats) so they are comfortable being pet.
For those of you commenters below who want to make sure their children are comfortable in normal adult society, I understand entirely. But forcing unwanted interaction is going to have the opposite effect.