In much of the West the ability to have children is economically or logistically (e.g. a career that would fall apart if they had kids) out of reach for many [1], leading many to perceive it as a selfish luxury. A "must be nice" kind of thing.

e.g. https://www.google.com/search?q=children+a+luxury+item

With this comes the perspective that every downside parents enjoy is earned if not poetically satisfying. It is amazing how absolutely without sympathy -- instead holding smug satisfaction -- people are if a parent faces obstacles.

[1] Obviously there are exceptions and different situations exist in different cultures and socioeconomic settings.