How odd. I mean it’s normal to say your children don’t need anything but why particularly do you feel children with seven siblings should be more forcefully excluded from gift giving? Are they in your eyes less part of Christmas?
It's common knowledge that, if you choose to have a very large family, that means your children will miss out on lots of opportunities that children in more normal-sized families get to enjoy. It's not the kids' fault, but it is their lot in life.
For example, if you ask a friend if they have a spare seat or two in their car to take your kids with theirs to an activity - nobody is ever going to have a spare 8 seats; or if you're hoping to stay with friends for a visit or event near where they live, they may be able to make room to squeeze in a family of 3 or 4, but a family of 10: clearly no chance whatsoever.
Parents who realise this and still decide to go on to have loads of children will surely understand that they will have to do their best to step up and make up the difference to their kids - buy a minibus and drive their kids themselves instead of grabbing a lift with others, or pay for several hotel rooms instead of staying over with friends. If they can't or won't do this, sadly the kids will just have to miss out. In certain circumstances, I believe that choosing to have a load of kids can actually lead to being a form of deliberate neglect, if not abuse. Even where there is genuine love and care, most people will want the best for their children - and (just my opinion) I believe that bringing them up having to share everything (time, money, resources, attention etc.) with 7 other children is most probably not providing them with the best.
Most people realise that, if you choose to have a lot more of an expensive 'thing' than most people do, your total expense will be far higher. Little kids first learn this concept in the sweet shop. I don't think the children should get fewer presents in this scenario, but the parents should make good the difference themselves and bear the additional costs, rather than expecting to stretch the goodwill of others to the absolute limit - often beyond what they can pay as much as are willing to pay.