"I might find that it's a massive amount of stress to put myself through at a time that is already likely to be one of the most stressful in my life".
You might indeed find this. And the less informed and prepared you are, and the more you doubt your ability to do it, the more stressful and difficult you are likely to find it.
"You don't have the right to stand on your high horse and tell me that if I choose to formula feed I'm damaging my child."
Any choice you make might damage your child. Welcome to the world of parenting. How you choose to feed your baby is not a consequence free decision, no matter what you do, breastfeed or formula feed. The science appears to tell us that some babies are harmed by not having breast milk. I appreciate that if you are worried about breastfeeding not working, then it might be hard to accept this, but we don't have to pretend it's not true just to protect your feelings.
"even then it's still not clear cut, breastfeeding is one of the most effective ways of transmitting the HIV virus from mother to baby for example"
Actually breastfeeding is a very inefficient way of transmitting HIV if complementary feeding (ie mixed feeding or giving solids) is not taking place. This is why in areas where formula is too expensive to use safely as the sole food for babies, HIV+ mothers are being encouraged to exclusively breastfeed for six months, and then switch completely to formula. This saves lives and results in a HIV transmission rate of less than 4%.
"because from what I've read, it's just not true."
What have you read then? I arrived at my views from reading a range of evidence on this subject including large scale reviews of the evidence, rather than looking at individual studies. and reading shite articles in the Daily Mail. I have a fair amount of trust in UNICEF here who do breastfeeding training, support and accreditation across the NHS and are linked to the World Health Organisation. Who is your trusted source of information on this topic?
"breastmilk contains some magical property that protects against all infectious diseases (it doesn't), surely infants in the West would be more likely to suffer life threatening illnesses, not less?"
Umm, there's nothing 'magical' in breastmilk, just antiviral, antibacterial agents, and ANTIBODIES. You know, those things nature puts in a baby's natural food to compensate for the fact that they are born with immature immune systems and are therefore more vulnerable to infections than older children and adults.
Babies in developing countries who have been innoculated, who live in decent housing, have access to clean water, medical care and parents who are healthy and not starving, are no more vulnerable to infections than Western babies. Less vulnerable in fact, if they are fully breastfed.
UK babies still get respitory illnesses like bronchiolitis, plus ear infections and gastric illness. And fully ff babies get these minor infections more often than fully breastfed babies, which is why as a group they clock up more GP appointments and hospital visits than fully bf babies.
That's not to say you should breastfeed or that your baby will be unwell if you don't. Most babies in the UK are still healthy and happy, even if their diet is not the ideal. This is also true of older children, many of whom in the UK eat god-awful disgusting diets.