Patching with OPatch

Hmm, sometimes life is funny. If I say to you that I have a generic patch, you would expect one patch that can be applied to all versions.
Not in this case.
I need to apply a patch for the Oracle IDM Suite (10.1.4).
Finding the patch is already difficult - and then there are four versions of the same patch - apparently based on different versions of the underlying J2EE. In my opinion this is not generic.

Trial and error led me to one of the four versions - which then came back with:
OPatch detects your platform as 46 while this patch xxxxxxx supports platforms:
0 (Generic Platform)

So again - it seems that my definition of generic differs from Oracle's view. I would understand an error, if the patch was for platform 46 or 18 or whatever.
But here a generic patch is apparently not applicable for my platform.

Luckily Metalink Note 404473.1 offers a solution.
So setting the following:

export OPATCH_PLATFORM_ID=0

does trick the opatch into believing that it is no Linux machine any longer.
Running opatch apply now works.

Still leaves me puzzled about the meaning of GENERIC.