Minecraft ignores java proxy parameters

The bug

As of snapshot 13w41b, Minecraft ignores the following JVM proxy parameters:

-DsocksProxyHost=* -DsocksProxyPort=*

How to reproduce

I assume the server list is not empty and the port 5678 is not used

1. Create a new profile
2. Choose 1.6.4 version and add the following JVM arguments:

   -DsocksProxyHost=localhost -DsocksProxyPort=5678
   

3. Play and look at the server list
   → There are communication errors (i.e. the proxy is used)
4. Quit
5. Edit the profile, choose the version 1.7.2 and save
6. Play and look at the server list
   → No communication error (i.e. the proxy is not used)