When books became affordable for the masses, adults of the day lamented about kids and books. Some even went so far as terming the "fad" reading rage or book lust. Point is, we (the older of society) will always piss and moan about the new tech our kids are embracing and predict calamity because of it.
Is social media healthy for kids? Depends entirely on the child, the media consumed, and the parents. For example, it is good for your kids to accept that fair compensation for labor is not something which can be provided top down. It must be acquired by the laborer. This is counter to your ideals but your kids would be better equipped for life if they be exposed to reality and accepted it.