I stand by there being an expectation for a level of reciprocity. It doesn't need to be equal, it doesn't need to be identical, but it does need to be something. Because otherwise if there's never anything in it for me, it won't continue.
My DC seeing their friend, yep, worthwhile. But if they have a number of friends and this one isn't a bestie then I doubt I would prioritise, but I wouldn't stop it.
Me spending time with a friend, again, there is something in it for me, spending time with someone I like.
Them picking up my DC from school and spending an hour playing at the park, brilliant.
Them including my Dc by taking them out on excursions, even if just a picnic at the park, again, it's some form of reciprocity.
Even then just buying me a cup of tea when we collect our DC from an activity as a thank you goes a hell of a long way!
If they have an issue then I would hope they could share it with me so that I could be understanding, but if they don't share how do I know if there is an issue or whether they just can't be arsed?
My life is hard enough that I don't have the bandwidth to carry the responsibility for others.