I think it is all just creating a 'science' around a tiny window of around 2 months max where some babies transition onto solids graudually using softer textured foods.
I'm not entirely convinced that the fibre component of a food is destroyed by pureeing. I would need a scientific explanation of that. Generally it is difficult to change the state of matter, and usually chopping up no matter how small doesn't do that. Otherwise, why would prune juice still have the explosive impact that it does?
The vast majority of children of today will have been weaned on to purees - and only a tiny minority of those will have food issues. That tends suggest to me, that pureeing of itself is not an indicator of whether children will be 'fussy' eaters.
Anecodotal, I know - but my DCs were weaned onto purees (home made) and they have a very wideranging palate - and have never suffered from constipation.
I do think there is an age (around 18m to 2y) where children do naturally become more fussy about what they eat. However, this is jusst a phase and the vast majority of children pass through it smoothly.
In summary, I see no burning platform - no need to change what generations of parents have adopted as the norm. Nevertheless, I cannot see BLW as being harmful, so if it floats your boat then go for it. However, I would advise, not to make a science out of something where there is no hard evidence to support your view point!