As PA Bear already pointed out, nobody here works for or represents Microsoft.
Therefore, we are unable to provide useful answers to questions about
Microsoft's motives for doing something.
If you need technical assistance to remove the update or prevent it from
reinstalling, we'll be happy to help.
... on the technical side, I will add a few corrections: strictly speaking
Windows Update is not installing the add-on. The add-on is a part of .NET,
which Windows Update will install, if you permit it to do so.
It should also be noted that the "uninstall" option Microsoft added was purely
cosmetic - there isn't really anything to uninstall, so if "uninstall" has
stopped working, "disable" is just as good.