Is NuGet really open source?

So about 6 months ago I submitted a patch to try to fix the out of memory exception that we were getting with NuGet, due to having large packages.

The reason I discovered this was because I wrote a tool that emulated apt-get using NuGet that is on my github. I really saw the potential with using nuget for .NET projects.

Unfortunately my patch got rejected after a 6 month code review with the following message:

To update everyone on this issue, I'm planning to reduce the overall usage of MemoryStream in NuGet.Core. In many cases, we load the package contents into memory unnecessarily, hence the OOM exception. It will address the issue better than trying to band-aid it with writing to a temporary file, which could potentially affect perf. I'm sorry to decline the pull request, but rest assured that the OOM exception will get fixed in 2.3.

So why the disappointment? Well rather than work in a open source way Microsoft decides that they can do it better. It is just sad that this software giant does not understand OSS.