Define “right”

Is the adult child in university? Maybe it’s right for parents to help them pay for school, if they can afford it.

Is the adult child straight to work and making their own income? Probably fine to not support them

Is the child a teenager, and working part time? Make them pay for their own phone plan, and put money aside into savings each month, to teach them how to manage a budget so they are prepared for adulthood. Still obviously cover everything else they need.