I sort of agree with both the answers you've been given, but essentially, no, turning the compost pile does not slow down decomposition over time.
It is perceived wisdom that turning a compost heap regularly will mean that the resulting compost is ready much quicker, and will be suitable for use in potting soil mixes because the heat generated in a turned heap means weed seeds and pathogens will have been destroyed. Climate where you are makes a difference - in hotter places, turning the heap may be essential to cool it down temporarily, but in temperate regions, its unlikely the average compost heap will get hot enough to destroy pathogens, and will take longer to turn into compost,see here for the standard advice http://www.homecompostingmadeeasy.com/turningcompost.html. Basically, the choice is between a faster hot, aerobic heap (turned regularly) or a slower cold, anaerobic one (not turned).
Your very interesting time lapsed video link shows a leaf litter layer rather than an actual compost pile comprised of different materials, and all it demonstrates is that soil without life forms means that anything sitting on top will take forever to decompose, although you can see green mould or fungal activity beginning on the inert side. There are various ways a heap breaks down, and it's not just burrowing insects,but also bacterial and fungal activity that may not be readily visible.
This 'fun' article here https://www.theguardian.com/lifeandstyle/gardening-blog/2011/sep/02/friday-debate-compost-turning cites two horticultural opinions that say it's not worth it on the strength that life's too short, largely, but in fact, being really scientific and rigorous about managing (turning, controlling moisture and content,covering, etc) compost heaps does mean achieving useable compost much faster.
Ultimately, it depends what you're going to do with the resulting compost from your pile and how soon you want it. If you're just going to put it back into the ground and you're not in any major hurry, or don't have sufficient time to take on the job (and most of us don't) then just leaving it to get on with it is fine. On the other hand, if you have the time and interest, then monitoring,turning, and so on, on a regular basis, will produce compost faster which will be pathogen/weed seed free and suitable for use in potting soil mixes, despite the temporary, short lived cooling and disruptive effect of turning.