I think the thing is, from speaking to health professionals and reading things etc., that the 6month guideline changed everything. This is what I have been told, as 'fact', by a variety of sources, summed up:
Babies do not have a developed enough stomach/digestive system to process 'normal' food until 6months.
Back in the day, babies were weaned from as young as 6 weeks because people believed that their crying meant they were hungry (amongst other reasons).
As a result, purees were 'invented' because the babies digestive systems couldn't handle un-pureed food.
Now the guidelines have changed to 6months, purees are now unnecessary. A baby at 6months can eat the same food as adults, albeit with less salt, additives, and smaller portions.
Therefore, if you follow the guidelines and wait until 6months, you don't need to puree feed.
However, the weaning 'system' of stage 1, stage 2 etc. is still widely promoted and advertised because a whole industry relies on it (Cow&Gate, Heinz etc). You only need to follow the stage system if you need to puree feed. You only need to puree feed if you start before 6months, because babies need their food puree'd before this age because they have undeveloped digestive systems.
To save confusion, this process of eliminating purees altogether (rather than continuing with purees and supplementing with finger foods and slowly making a transition to 'normal' foods) got given a name: baby-led weaning. Since then, baby-led weaning has picked up more things, such as not spoon feeding your child at all (even cereals and yoghurt) so has become more of a genre in it's own rather than just being skipping purees which has caused more confusion.
The end.
Yet, despite all this, everyone will do things their own way, hence we now have people who BLW before 6months, people who puree feed before 6months, people who puree feed after 6months, and people who do a combination of both either side of 6months.
If you follow the guidelines and wait until 6months, you do not need to start with purees, why people choose to, I don't know, it just seems like a waste of time, effort, and money to me, but it is so instilled in us to start with purees (after years of the start time being 4 months) that it's just habit I think, not to mention it's not seen as 'the norm' and people worry about choking and stuff. Equally, if you're a fan of BLW, I don't see why you'd start before 6months as the whole point of the creation of purees is that a baby's digestive system can't cope with "solid" food until 6months, but again, people have their own personal reasons.
Just so no-one thinks I'm some big preachy BLW, and to answer the original question of "is everyone against traditional weaning?" I did wait until 6months, and on the advice of my health visitor (who had never heard of "BLW" as a term/concept) I began with finger foods. I did read the Gill Rapley book and do a lot of reading around the subject and saw the reasons for waiting until 6months and not using purees and they seemed to make sense (ie. obesity/portion control, the development of the digestive system & allergies, intolerances, IBS etc etc) so I went with it. If people ask, I say I BLW because people seem to know that the term means he just eats what I eat, but I do spoon feed him yoghurts, and he prefers it usually if I tear bit of food off and hand them to him. He's also very active and curious (and moody) and refuses to eat breakfast at the table and likes to chew on a bit of a toast while he plays. He then comes over to me and opens his mouth like a bird for me to put pieces in. Bizarrely, he then takes these pieces out of his mouth, examines them, and puts them back in to eat them, he just won't take them off a plate and put them in his mouth. All this is just for the one meal of breakfast, he eats like a 'normal' BLW baby at lunch and dinner. Go figure. So on paper, I don't follow all the 'rules' of BLW, I do what works for my child.
I don't think people are against TW at all. I think the majority of people are misinformed and this causes all sorts of problems on both sides. I do not know anyone else in my day-to-day life who baby-led weans. Everyone I know started with purees at 17 weeks. Therefore, I'm the one who is judged, sneered at, or that people are 'against'. Only recently are health visitors being educated about BLW, and even that causes confusion because nutritionists are refusing to promote it as it has no scientifically proven benefits over 'traditional' weaning as of yet. But in my opinion it's not about proven benefits over TW, it's about being equal in nutritional value to TW but just coming at it from an easier and cheaper angle. And even those nutritionists advise waiting until 6months.
Anywho, that's my 2cents. Like a lot of ladies have said, it's about educating yourself and others on the guidelines. It's irresponsible, in my opinion, to make a decision without looking into the reasons for and against it, especially when it comes to a childs wellbeing. We have so much information at our fingertips with libraries, children & family centres, health professionals, helplines and the internet that there really is no excuse for people to stumble blindly making irrational choices. If you read some of the information and make a decision that other people don't like, as long as it isn't child cruelty or whatever then it really is none of their business.
Sorry for waffling but now I've put across all the facts I know of, my job here is done, lol. I just thought I'd try and help clear up some of the confusion over TW/BLW and the associated guidelines.