The suffering involved by those desperate for children but unable to have them for whatever reason isn’t really a coherent argument in and of itself. The suffering of one group of people has no bearing on the moral/ethical violations that come from the exploitation of women nor the commodification of babies.
Those who are unable to conceive comes from a medical condition. It is not incumbent on humanity to rectify that if it means exploitation of others. You can make a utilitarian argument if you wish, but you’d have to establish that there would be less suffering overall, and I’ve not seen any pro-surrogacy advocates put in the leg work to establish this. Plus the same utilitarian base could be used to legitimise organ harvesting for commercial purposes.
Other than that it’s just an appeal to emotion which honestly both sides in the debate can utilise so it doesn’t really resolve anything.
There is also an environmental dimension to the discussion in that our planet and birth rates are potentially catastrophically high. One of the most polluting things we can do is to make more people. Seeking to bypass any and all natural pressures on population growth and the effects on the environment is also a consideration.
Yes I am lucky enough to be a parent, yes I have have sympathy for those that don’t, but my status as a parent doesn’t affect the validity of my argument. I am very happy to throw public funds towards people who cannot conceive for therapy to help them come to terms with that, but not to inflict exploitation upon others.