1. Taxes are more punishing because you're spending half your disposable income on children, and most of it probably comes from one earner. You can say "don't have children if you can't afford it" all you like, but you wouldn't be alive if nobody had children, so it's quite selfish of anyone to be anti-children.

2. For men performance expectations are the same but now you have to somehow simultaneously be at work and also pick up your children from school at 3pm. Oh and don't forget you have to somehow cover like 80 days of school holidays a year. For women... well you can legislate that being off work for 2 years doesn't matter all you want; in reality it is a major disruption to careers.

3. Childcare is far more expensive than any increased cost I experienced for being single, with the possible exception of not being able to share rent with a partner. But once you have children... rent for a family is more than double rent for a one bed flat.

4. Yeah price me up a skiing holiday for a family of 4. Now do it for a single person (and double it if you like).

The very reason that discounted family tickets exist is that families wouldn't buy any tickets otherwise because they would be too expensive. It's the same reason student discounts exist. It's called price discrimination.

I do agree it's pretty annoying and feels unfair though. The optimum group from a price point of view is really a couple, not a family.