I was under the impression that you were already implying that it was down to Microsoft as an intentional act. My apologies if I got that wrong.
I was not implying anything other then there seems to be an issue with the latest changes to Windows Defender that is affecting a couple other Vendors as well. Norton "well known product" of the two, has the very same issue upon a clean install as Eset has been facing.
Imagine you just cleanly installed your system, and placed Norton Security on, and all looks well, until you go to check your security status, and notice both the firewall and Av section missing in it, you then open Windows Defender Security Center to see Windows defender stating that it is off and urging you to "turn it on" while at the same time not recognizing the product you just installed, or even worse yet, you open the security center and find both Windows Default Security "windows defender & Firewall" are running along side you 3rd party Internet security suite because it was not recognized. This, is what is happening with Both products I have listed and tested.
This statement alone by a MS representative is enough to make you question Microsoft's stance, and is certainly not the first time I have heard a MS representative claim such non sense.
In a sensational claim, Kaspersky says that a customer in France was told by a Microsoft representative that "Windows 10 is incompatible with third-party antivirus. It's a shame that you've spent money on a Kaspersky Lab product, but you can't reinstall it without running the risk of the appearance of new bugs."
Microsoft causes issues all the time - one way or another.
1. unannounced changes
2. more strict policies without notice
3. undocumented stuff
4. unilaterally making changes without consulting anyone
I don't think it really matters anyway, it doesn't affect me or anyone I know and I've been unable to replicate it.
Good debate though
If the users you know are already running security on their system before the update, then you probably will not see an issue. It is clean installs of both Vendors I mentioned that are affected. Which means any further selling and installing of their products will be hampered until they can find a work around.
This was an unnecessary debate, a good look at the article tells much, and the link I posted provides more proof that the changes made recently, have certainly affected some 3rd party products.