What i have noticed over the past years, are more SMs responding and actually telling the OP - they are wrong and what they are doing is cruel, or to keep at it - this is right.
Case in point in the last few weeks of SM changing well established communication patterns. V good, not nasty, sensible discussion, with different views, bananas - suggesting one thing and others suggesting other things.
Where SM wants to buy SCs cheaper school uniform than their half sibs, when it is their year to buy unform. Rightly got told to suck it up!!!!
I dislike the quite nasty picky comments about how the Ex parents badly - over small things - not abandonment in your case. Eg strict bed times, money etc.There is an assumption sometimes that the issue is because of the EX - with little back up information - that is actually known.
Mostly I have learnt how little things get blown out of all proportion very quickly and stuff that one lets sail by in your own kids becomes the biggest blow up with a SC, sometimes I laugh.
I think we expect an awful lot of SCs, to accept a situation, live with different rules, see less of one parent than they would like, like, treat with respect the new parent, miss out on stuff because of what ever issue, stick to a timetable of contact that does not actually consider their stability and is for the parents not the child, change clothes, toys etc. That is not a reason to pander to them but sometimes - the intransigence of the adult, steps, own parents etc is more childish than the children themselves.
Like I said, I have learnt alot