Most of the 'negativity' is a beat-up by the great unwashed...who are leery of the 'free update' model and claim there MUST be a catch. [even if they need to fabricate it].
This remains to be seen - I stand by my statement and what will turn out to be 'common' understandings in the future will bear this out. There is a likelihood that some of these issues are quietly remedied, however, in which case joe-six pack may be none the wiser. This is especially true in the corporate world where, for example, many companies do not allow the use of SIRI, lest trade secrets be stored offsite by someone else - how, for example these data captures will comply with HIPAA or FINRA remain to be seen - and may very well end up in court..
It is only a matter of time before similar stories start appearing with respect to Apple, MS and FB.
For example, Apple's introduced use of end to end encryption for communication is thought to be a response to the pervasive use of warrants issued against Apple users for data (ie Apple itself cannot unencrypt the data, thus are unable to comply). Similarly Google has taken great lengths to shore up its encryption internally after it was discovered that government snoops were finding unencrypted data being passed back and forth inside their data-centers. MS is currently embroiled in a lawsuit with the federal government over whether data kept in server farms in Ireland are within the jurisdiction of US law enforcement (presumably to spy on someone). FB, as far as I can tell, generates tones of data, but doesn't really know what to do with it and is also sloppy about it - the preliminary reports coming in from its phone app (I honestly have no idea why anyone uses FB, but I digress) is that its creepy microphone recording feature will intermittently turn on to sell you more targeted ads..
See here's the thing. What this shows is both the value of this information to various parties, and also the individual danger they may potentially pose. So companies are doing their best to acquire/generate more of it (because it's valuable), but then also to safeguard it (because presumably it becomes worth less if everyone else has it, and also because users may attempt to styme it if they feel that it is somehow unsafe or insecure). However, ultimately these two goals are contradictory and ultimately will prove to be irreconcilable.
I don't think that this thread has been hijacked, my interpretation was that the OP was asking why people didn't like W10. Apart from seeing no specific benefit over, say 8.1, I'm of the mindset that the privacy concerns are a valid concern. Sure, you're going to be spied on anyway (this rebuttal should point out just how bad the overall level of privacy in society has become), but honestly - why make it easier for everyone?
If you want a legit and above the board reason for MS to give W10 away for free - it's because supporting only 1 legacy OS is a lot cheaper than 3, or 4 or whatever it is. Streamlining platforms means streamlining development, support, and all the rest.. This is a good reason - but like most things, it is unlikely to be the only reason..