The 'just use contraception' argument has so many fallacies.
In many areas of the UK, it can be really hard to get a GP or practice nurse appt for contraception. Sexual health clinics are closing/few and far between. For coil and implant fittings, there's a lack of specially trained staff to put them in and you have an appointment wait if you can get one.
The pill is not suitable for all women (due to risk factors/other health conditions) and will not work if you're sick, on certain medications, or you miss doses.
Coils and implants can go wrong (and not all women can have them due to risk factors, health conditions, uterine physiology). There is the depo injection but you need to try to get an appointment for this and, again, it's not suitable for all women.
The MAP in the UK is quite costly---can be hard to get an NHS script. So if your choice is food for the week or the £13-25 for the MAP, what are you going to choose?
Just wear condoms, you say, but this is subject to your partner also---so many men refuse to wear them. So don't have sex then, eh?? Is it always consensual? What about the sexual coercion or pressure put on a woman to have sex. Having sex with one's DP is not always a real choice for a woman and for those saying 'just don't have sex' are a bit out of touch with reality
Added to which, NO contraception is 100%. Abortion is a fallback measure.
We are lucky in the UK that most contraception is free (for now). In the US, it is not so that is another barrier to access.