Wouldn't it be more helpful if, instead of just saying "Don't do this upgrade" you gave us some reasons not to ? What's so poisonous about it ?
Personally not having any problems with Win10 upgrades
Well, after the (admittedly) rather sensationalist instruction not to upgrade there is a link.
Clicking on the link will take you to an article headlined:
'Stuck installing the Windows 10 Anniversary Update? Here we show you the most common problems and how to fix them.'
Which it does, therefore giving reasons not to install the upgrade which in turn would also explain what's so poisonous about it, as you put it.
The same article also gives solutions and workarounds to the more common problems encountered when applying this latest Microsoft 'upgrade'
On a side note I fail to see how making Cortana more prominent is an upgrade, I'd consider being able to uninstall this annoying feature a good upgrade, not giving it more importance.