This was done on purpose. As you can see, forcing the use of the debug libraries causes link errors.
Epic has decided to link against the Release version of the CRT, even for the Debug configuration. Our own Debug libraries still use the Debug CRT, so trying to use them in UE causes link errors.
The profile libraries still allow you to connect the Wwise Profiler to your game. The only difference between Debug and Profile is that the Profile libraries are optimized, so we decided to use them for the Debug configuration, avoiding the link error.
If you absolutely need to use the Debug version of our libraries, Epic has exposed an option in their build pipeline to enable the use of the Debug CRT, thus allowing the use of our Debug libraries. Simply set bDebugBuildsActuallyUseDebugCRT to true in BuildConfiguration.cs. This is not the recommended method, though, as the performance hit is significant.