People as a whole aren't very good about or motivated to look up evidence around contentious topics. Most parents tend to get their information about what's good/bad from peers. I remember during pregnancy my friends all talking about how horrific sleep training is, how damaging it is, how cruel it is, and just going along with it assuming that it must be true for them to feel so strongly about it. Then during pregnancy while reading up on the evidence around various parenting decisions I was surprised to find that that isn't the case. There's a wealth of evidence it's effective, and no evidence it's harmful. I adjusted my view in light of this, but some won't as they'll hold onto what they previously believed.
It's one of those things I think, nobody HAS to sleep train, and I don't judge people who choose not to (though I do feel sorry for their child if they're an awful sleeper and nothing is being done to try and improve it), but it's important that people aren't fed misinformation so they can make the right decision for their child. Some would choose not to sleep train even if they understood the evidence behind it, and that's fine. But it's great to let people know it's an option and that there's nothing backing up the assertion that it's damaging or impacts attachment and so forth.
It's an emotive topic but I've definitely noticed the tide changing and people being more educated on things like sleep and infant feeding (the 'breast is best' movement thankfully is dying a slow death and there's so much more awareness of the fact that there is no universal 'best' for every family, it's so individual and so many of the stated benefits of breastfeeding aren't backed up by the evidence). It's nice to see! Parents are already under so much pressure without misinformation to boot.
It's human nature also to find it difficult to put yourself in someone else's shoes and understand why they might choose to make the decision they do. It's unfortunate that in many parenting forums when a new parent posts saying that their 6m old baby is sleeping 30m at a time and they're at the end of their rope and their mental health is shattered and they can't even think about returning to work and they can't drive safely and their marriage is in tatters... that they response is often 'what did you expect? This is normal. It will pass. Keep going' even if the person has clearly stated they can't keep going. It's helpful to balance out that kind of normalising support with information about what they can DO to improve the situation.
I don't think everyone understands the level of privilege it requires to be able to tolerate, indefinitely, for months at a time, being woken up every hour throughout the night. Many people have jobs that they need to be rested to do safely, my DH could literally kill someone at work if he went in exhausted. They might have older children to care for, or have no choice but to drive as the nearest supermarket is miles away. They might have no family or friends around to 'take a shift' overnight, or they may be a single parent. They might (and this is common) have mental or physical health problems that are exacerbated by poor sleep, and their mental health might be pushed into a dangerous place if they continue to be unable to get adequate rest.
Sleep is a human need and it's easy if you have a baby that sleeps two hour stretches through the night to think sleep training parents are being cruel or just wusses who don't realise that parenting continues throughout the night. Until you're in the shoes of someone who absolutely cannot continue one more night the way things are, you shouldn't judge. That's not to say that's the only circumstance where it's appropriate, of course, it's absolutely normal and natural to want to help your baby get better quality sleep regardless of what else is going on. To me it's a fundamental part of parenting. Good quality restful sleep is crucial for wellbeing and brain development and while you may choose to wait it out and see if sleep gets better eventually it's not the only option. Anecdotally I have several friends who didn't sleep train their terrible sleepers and now they're toddlers waking every two hours throughout the night needing to be fed or rocked back to sleep they desperately wish they had.